I would recommend HTS. They are stand up people and I have dealt with them a couple times to get parts to build up the trans to simply get rid of the crappy factory parts. This mainly revolves around the valve body. Not getting into detail but the clogged up gov pressure solenoids is due to clutch material in the trans. Replacing it with a GM solenoid as some have done simply hides the problem. Crappy (slipping) shifting causing that debris from the clutches.
Point is, make it shift right and it will last longer.
I kept my factory converter and had the valve body front band, shift lever, and accumulator replaced 3 years ago. Had issues with front pumps going out and converters crapping out since but shifts like a champ. If I did not have a warranty on the truck I probably would have opted for a better converter the stock one.
I would recommend getting one of their built transmissions and sending yours back as a core. Call them and tell them what you are doing with the truck and they will steer you in the right direction. No sense getting triple disk converter, red clutches, all billet shafts, etc. If you never intend to go forced induction. You get the point. Have the trans built to your needs so you are not just throwing money away.
You can always try to just buy parts to fix yours. But if you had a snap ring in the bottom of your pan I would guess there is crap in your converter, not sure if that can be flushed out, might have to replace it and they are not cheap. Don't think you are going to get a $300-$500 fix that will last.