What answer are you looking for? The best advice for adjusting fluid to work with your converter/transmission setup is to hit up the transmission builder or converter builder.
Some types of tractor hydraulic fluid (I used to run Hy-Guard) will tighten the converter, but it may also jack your clutches if they're not compatible. Depending on what components are in your converter and transmission, the answer can vary quite a bit.
All that said, yes, I ran the Hy-Guard because it tightened up my 4800 RPM stall for driving around on the street. It also had a big temperature tolerance before "burning". That was in my Rossler 'glide.
-Blake