I have an older T/A FMVB #17675 which they don't make anymore. Ten years ago when I built my transmission, I talked to Paul about it and he said pressure will be 130psi. Don't quote me on this but a RMVB should create more pressure, like 140psi +.
Again, I have not run it since I built it but once it's in the car I can experiment with it since it's easy to do. From a S.O.T.P. perspective, my old 904 that was built very similarly using the same valve body shifted HARD.
If you are referring to the race case from A&A, I'm not sure. They don't list that modification specifically in their description. I'm sure they could do it if you asked. I didn't watch any video but my guess is it's probably not necessary for most applications. Also, if he was talking about it for a 727 that idea may not apply to a 904 the same way.
I provided the link to the A&A case in post #10 but here is the copy:
"These cases are machined to allow pressure adjustments while still in the car. They have a cut-out in the bell housing for easier converter bolt access. Lubrication and venting has been improved. Each case is glass beaded, bores are honed, bolt holes are tapped and looks brand new."
I looked around to see what kind of blingy parts for 904s are available, click the links below;
TCS offers
a billet front drum and an
aluminum pressure plate kit.
A&A also has
billet aluminum drum stuff,
roller parts and
lightened sun shells.
Far as I can tell from their website, CRT does not seem to list much in the way of 904-specific parts. I imagine they could suggest and obtain whatever you want though.
The ultimate unit would probably be a Pro Flite but those are $6-7K+.