The ram on the accelerator is 32-bit and the RAM on the GVP sidecar is 16-bit. You can use both simultaneously but you'll need to run a 3rd party "hack" early in your startup sequence to get it all to "play nice". I ran the same setup for years and had an A500 with 18MB of RAM (8MB 32-bit fast, 8MB 16-bit fast, 2MB chip). Even bought faster CPU & FPU and overclocked the VXL a bit. Could never find the correct PAL's to get it to support the 50MHz mode but I was able to give it a "bit of a bump" by trying different oscillators.
Like you my RAM-32 board eventually started to fail and the system will only boot if I disable it (by commenting out the third party tool in startup-sequence). The system runs like a dog with only 16-bit RAM and honestly I haven't had time to even turn it on in a couple years to mess with it. Maybe one of these days I'll hunt up an alternate internal accelerator to replace the VXL.
Sorry no real input on your questions, just popping by the forum for a sec and wanted to share since I have a very similar config to yours. Good luck!
