Yeah I never did that with 4 speeds, I figured there was a way to tune for it with a CTC. For my personal experience I won't be doing this again, but...
I found some overlaps on my 5-6 and 6-5 that made a big difference. Helped get it to stay locked too. I also had to back my WOT shift points down so...
I dont even know where to start with this thing. Attached the tune for reference. Id acquired a bastard 07 GMT900 RCSB V6 Silverado without the FPCM....