All of this advice, together, will solve most of your problem.. The heat and moisture have to be managed correctly, and that is a touchy-feely OJT. I have found a help with turning is in the form of a rounded hammer handle, wood and as smooth as you can get it, tightened in the vice and used as an anvil.
Start at the rounded outside corner of your inside-out pouch and push allowing the hammer to force the leather to turn the seam. Work the second corner the same way, and then go to each edge of the seam at the top of the pouch. Turn the tops and then Knead and push firmly on what will be the bottom of the pouch, evenly without feeling like you are forcing or bullying the leather. A little here and a little there will progressively get your bag turned.
Lastly, once turned to your satisfaction, run the inside of the seam over the top of your anvil to even the fold out. This works really well if you have welted your seam.
Hope this helps