I haven’t used G+ and am not balking at the cost. My biggest issue is going into the day without my must do rides being guaranteed, as they were with FP+. I wouldn’t mind spending the $$ but I do want to ensure I get to ride the most important rides to me if I am spending that $$ and only going to WDW once a year at best (haven’t been since July 2019).
Depending on what rides you want to guarantee you'll get, I think you'd be OK getting 3 guaranteed rides, whether you buy G+ or not.
Just food for thought - if the 2 ILL$ rides are your "must dos", you can opt to pay for both of them and select a time slot to ride them in the morning. Most ILL$ rides don't sell out until 10am or later.
If you're staying onsite, you can buy your ILL$ rides at 7am, and that should guarantee you ride them.
Also if you're staying on site, the 30 minute rope drop advantage means you should be able to get on 1 ride with a short wait. That could be an ILL$ ride.
FP+ gave you 3 rides pre-selected, so I'm going to assume you have 3 must-do rides... also going to assume you're staying on site.
Using Hollywood Studios as an example, lets say Rise of the Resistance, Slinky Dog Dash and Mickey's Runaway Railway are your must-do attractions. Here is what I would do... if I didn't want to pay for anything.
1. Get to the park at 8am, for rope drop.
1. 8:30am - Rope drop, Go to Rise of the Resistance, wait time should be ~45 mins or less (assuming it doesn't break down).
2. 9:15am - Head to Mickey's Runaway Railway, expected wait is roughly 34 minutes.
3. 10:00am - Hit up Slinky Dog Dash, expected wait time is 45 minutes, or you can wait and ride Slinky Dog after 5pm where wait times should be 45 minutes or less as well.
Note: The expected wait times are not the posted wait times, they're estimates based on what the actual wait times of past riders has told us (using the Lines App).
If you bought G+, I would try to select Slinky Dog as your first attraction, regardless of what time it gave you, and still rope drop RoTR and then do MMRR.
If you choose to buy the ILL$ for RoTR and MMRR, I would rope drop Slinky Dog, and then either not buy G+ or if you bought G+, I would then select whatever ride was my 4th must do.
If your 3 must do rides are not ILL$ rides, then I would rope drop whichever is the most popular (like Slinky Dog) at 8:30am, then try to ride your next must-do ride immediately after, and then wait until 5pm or later to ride your next must-do ride or monitor wait times and see if here is an deal time before 5pm to ride. In between you can still choose to ride other rides. If you buy G+, you can select your first ride at 7am, rope drop a second ride and then try to hit your 3rd ride right after the first.
Yes, it is maybe a little more stressful if this is your once in awhile trip and you really want to hit your must do's since you can't pre-select them like FP+. I would consider investing in a TouringPlans subscription for $12/year and use their Lines App to help, it can even plan out your day for you and make sure you get on all of the rides you want. It should help remove some of the stress. The Lines App doesn't currently incorporate strategies for G+ or ILL$, although they do allow you to input a G+ or ILL$ time and it will optimize around it. They will in the future add strategies for ILL$ and LL.