Best focus screen for close focussing on Mamiya C330f?

I’m guessing No.5, but would appreciate info from those who have been there, done that. The only lens I have currently is the 80mm. I have the Paramender 2.

The No.5 is for focusing an aerial image. It takes practice to remember to check for parallax against the cross-hairs.

Do you have a problem with your current screen? The 80mm is f2.8, so even at full extension (not quite 1:1) the light loss will not be too bad.

I would use an all matte (#1) for close focus. Even for true macro. Telephoto screens (for smaller aperture lenses) are ideal, but I don't believe Mamiya made one. For high mag (ie: really small effective aperture) with high contrast flat items, an astro screen (ie: #5) can be useful.