Kent I would not change a thing it looks like you have a really well thought out setup. The 512 is a torque monster you do not need a high stall speed converter to go out and have fun. If it were a purpose bulit race car it's a different story.
I run a Hughes 3000 stall converter behind my little small block and I think it is great for the street. I also ran a 3000 stall in my 512 powered Satellite it also worked very well on the street. You have a Gear Venders dont worry about a little highway converter slippage.
Run it as is and if years form now you want to step up the game go with a custom converter as many here have suggested.
Happy motoring
