Hi Joe,
There are a bunch of variables here. 3600mah is a lot for 7 mins and maybe you need to work on throttle control. Moving to electric flight is a bit different to IC and it seems that many people initially fly too slow and then find the throttle stick and hit it a bit hard, maybe that's where you are at.
You also may want to look at timing on your Jeti 90; if you reduce the timing the motor will be more efficient but reduce the power available. Since you have buckets of power this may be worth looking at.
Unfortunately you are unlikely to solve the "practice time per battery pack", would be great to be able to fly practice flights for 15 mins or so but it's not going to happen with the current generation of battery packs, I set my timer for 10 mins and put back 3500 to 4000mah.
In terms of braking, I assume you want to increase the braking effectiveness. I use a Spin 99 which has a slightly different braking system, take your brake to 40% and see how it performs then increase/reduce from there until you are happy.
All the best, Simon