Zipper is correct just install cgx4 right away with the latest patch.
This latest patch (or an update of cgx4 after BB2 release date) is vital for correct working of CGX v4 with OS3.9 Boing Bag 2, it updates the cgxsystem.library if remember correctly.
If you do not install this patch CGX will not work at all with BB2.
Installed multiple A1200's with bppc+bvision perfectly this way and also A4000's with csppc+cvision.
The RC5 update is the correct one, just only install this update, no previous versions needed.
When installing the RC5 patch you do not have to do any renaming, just install the patch and reboot.
During boot (if you do not use a scandoubler etc. i use a m1538s for AGA)) the monitor connected to the Bvision should switch on and go in standby mode.
Select the bvision and desired screen res in the prefs, not all resolutions are defined at start, you'll have to create a whole bunch of them,a nice custom one is 1152x900x15
