1. Your old FP+ method is how they envisaged G+ working, according to some. And many people have good experiences doing that.
2. However the reality is that there are some rides which “sell out” of G+ passes early on. Even booking at 7am or thereabouts will get you a return time of 4pm or later. For those rides then clearly if you want to ride it using G+ you need to try for it early.
Also if you are park hopping there are good reasons for stacking G+ passes for your second park. Disney just recently made that a little more cumbersome, but the strategy still works.
I believe you can now see when you are eligible to book your next G+, so all you need do is set a reminder for 5-10 minutes before that.
Here's our experience (I am trying to piggyback on your comments, not replying to you specifically.)
1. OP's strategy sorta worked.
2. Two you need to book quickly are Slinky and Jungle Cruise. Otherwise, the rides that sell out quickly are the boarding groups for GoG (the ILL's last a while) and the ILL for Rise. (I think.)
3. With G+ it sorta makes sense to hop, but mostly only to MK or a park that will be open late. By mid-day, it is VERY slim pickings at Hollywood Studios, even on a slow day.
On busy days G+ gets overwhelmed, and doesn't work very well. One of the BIGGEST deceptions of G+ is that the time see is not the time you get when the system is busy. This is super important. You THINK you are booking a return time of 10am, but then when you get to the confirm screen, the time could be anything 10am, 1pm, 3pm, or sold out. From 7am to about 7:20am- no return times are visible on the first screen at all.
Even on slower days, G+ still gets overwhelmed at 7am. The G+ booking you make at 7am is a total _______. The actual return time could be anything, and you can't see what the actual time is until after you book it.
If your first pass is for a high demand attraction, then odds are high you'll have to stack your first pass for a time that is more than 2 hours after park opening.
You can cancel a pass, the options are terrible. If you cancel a stacked pass, there's no recourse. It is just gone. If you cancel and rebook your most recently booked G+ pass, then the 2 hour clock resets, but sometimes that is still your best option.
G+ stacking works pretty well if you are going to MK, and simply plan to arrive at MK after rope drop. SO LONG AS you actually DO get to MK. Stacking G+ is a bit like gambling. You are placing a bet that you will actually get to the park in that time frame. If the the transportation and weather stars align, you will get to use your passes and going from G+ pass to G+ pass is quick.
Pass return times can now overlap. One day, it was pretty funny because we actually had a HS pass for 6:40pm and an Epcot pass for 6:35pm.
The other thing we did this trip that worked really well was - more or less - to sacrifice a headliner in MK and HS. If you simply skip Rise and 7DMT, your day goes more smoothly. For HS, we only had to focus on getting Slinky. If you get Slinky, esp an early Slinky, your day goes well. If not, your day is somewhat crappy.
IT REALLY PAYS TO USE the Atomic clock APP! to know when it is 7am. Prior trip, we missed out on Slinky, even though our phones said it was exactly 7am. With the Atomic App, we got a very low BG number for GoG. I think we got 6 one day and like 8 the next time we tried.
Some G+ do sell out fairly early. Also important to know are the drop times. So once the park opens, I mostly focused on getting what-can-we-ride-now passes. It is a little the reverse of how we booked FP.
In the FP days, I aimed to get headliners. If you do that now, you'll only be able to book a pass every 2 hours. (Stacking). If you instead aim to book back-to-back passes, then you will be able to go from G+ to G+, at least in MK.
Weather is also factor. Lightning = many rides shut down. One night we hopped TO MK. Many rides were down, but we were able to book G+ back to back - BECAUSE we had not booked any of the attractions earlier in the day. If it looks like storms, then hopping to MK in the evening works very well. Little Mermaid had a 45minute standby wait, but not for us. If a ride is down, and you have a G+ pass, you get an anytime G+ pass.
WDW attractions are not running as reliably as they once did. No matter how well you stack G+, if EE is down all day, then you aren't riding it.
In the FP days, I didn't think hopping was worthwhile. When booking G+, MK is by far the best park. Though I say that with a small caveat, because for much of the rest of the year, MK closes at 6 or 7pm.
With some caveats hopping now is a good way to make the most use of G+. You can only book each attraction once, so the longer you stay in your AM park, the fewer attractions you are eligible to book. Hopping to HS or Epcot with the idea of stacking passes, isn't all that great of an option, because there's not much left to book mid-day or later, and AK closes early, unless it is a really slow day. It all depends though on park hours, how late you want to stay, and weather.
It was just my rough impression, but it seemed to us that G+ and crowd levels are very independent variables. On some days, the park was crowded, but G+ passes were easy to book. On another day, the MK standby lines were much shorter, but G+ had less availability. Maybe it was the number of people booking G+, or maybe WDW manipulated the quantity of G+ passes, not sure.
When booking a mid-morning pass, it paid to refresh and take a little time. We often saw a return times jump around. We'd get 1pm, 1pm, 1:05pm, 1:10pm, then suddenly 10:30am!
There were some crazy days where we had alarms set for when we could sue our passes, plus alarms set for booking our next pass, and it was a little messy. For each alarm, it helped to 'name' what each alarm meant. (ride Slinky, book G+)
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