Tranny & Diff Fluid Opinions

Getting ready to drain/refill the tranny and the diff in my 72 Slant 6/Automatic.

I know Dex III is recommended in the tranny, but read some people run, or you can run Type F. Opinions?

Also, what are you guys running in your diffs?

This is on a daily-driver. Looking for the best bang for the buck. Not looking to spend a ton right now, so spare me thge Amsoil/Royal Purple recommendations.

Thanks!