Oh yes, I can contribute to this. I have posted before about the quality of IMD Pistons. I was going to chip in during the last "pistons" topic - because IMD wasn't mentioned. I have just checked and IMD are coming out with new A10 stock soon (they weren't advertising them the last time I looked). They only do flat-top up to +40. Adrian Wright, the proprietor was very helpful, though - and supplied me with the flanged liners that our reconditioner insisted on. There's 2 others in our club that have followed my lead now, and sleeved back to std - by this.
I have done about 3k miles since I fitted them. I put them in dry (with light oil on the skirt only). I ran them in using the "stationery" method described by Klaus, a while back. They appeared to bed in instantly, then. I hopped the performance up by a bit of skimming (some was unavoidable, I shortened the pushrods correspondingly). This has raised the compression to about 8.1:1 (by my calculations). I fitted a 1 5/32 new Amal Premier carb. Since then, the bike has performed with a lot more power and burns no oil.
Our supreme guru local engineer was very impressed with them. He is very hot on piston quality (dislikes JPs). The other thing to mention is Adrian said "don't gap them - no need to". So, I didn't. The rings appear "modern" - thinner and deeper. The 3 piece oil ring is a big factor, I think. The pistons are light, too..
