I’ll add another thumbs-up for toppers on an aluminum flat lap. The Chinese versions from EBay are actually better than those sold in the US, in that they have more diamond and are very flat. Add the additional benefit of being half the price when compared to US manufactured disks and it is an unbeatable combination.
There is no need to purchase the toppers with the glue on the back. I just put a very fine mist of water on the aluminum flat lap before installing the topper. Easy.