I made that accelerator hack years ago. It is unreliable, unstable, and uncompatible. AdSpeed is only a small improvement, compatibility-wise.
Simply swapping in a 68010 (still 7 Mhz) is a better option than above.
The Supra Turbo28 is excellent and the best 16-bit accelerator. I use one in an A2000 and one in an A500. These show up on eBay for modest prices.
