Looking to source suitable heatsinks, I found these ones with their own thermal adhesive tape. Tape shouldn't be hard to remove, if required, with normal cleaning solvent.

For $2 including postage, hard to go wrong! Since my IIsi has been running for >20years without them, it can wait a few more weeks till they arrive from China.

Also looked at your mod with heatsinks, Uniserver. Can you still fit a NuBus card over the top of those? I'm not overclocking (yet) so I'm thinking I'll go for low-profile heatsinks about the height of the RAM sticks.

Rick