Well I have taken a risk, and fixed them to the some of the chips on my Acard as its waaaaaay too hot. And I'll tell you if they fall off.
Seems pretty good to me. And I was planning on putting 4 of them on my 68030. Good clean surface there, and will wedge under the TT Ram board. There were one or two other chips, cant remember what they are for or the name, but they seem to get a bit toasty when doing intensive apps. Funny, but if I put the TT under software load, they seemed to warm up!! (I doubt that this is power management like you get in the PC, but just caused by high throughput).
I have also made some adjustments to my PSU, but much more secure, as I really want this to last. I have adjusted the air flow internally, as it was a bit poor at cooling all of the heatsinks in original configuration.