This is all together different from the transmission question, but still in line with your build...
If you want a cheap stretch when you swap that 8.8 in, you can use stock LJ arms in the rear to net you about 10" of stretch. To complete it you'll need to put fuel cell behind the rear seat (no one makes one to allow for that much stretch and still being able to keep it under the tub), notch the frame for new upper spring buckets, move the shock mounts, and get a longer drive shaft. Then, just do your comp cut like your already planning.
If your on a tight budget and want a stretch you'll never do it cheaper then that.