We use 7x5 & 0-40% overlap for the K3 (seems like 40% may be optimal, but it’s definitely overkill). For K2, we used 5x5 or 7x7. The K3 is more elongated, so the extra patches seem important. The K2 and Falcon are nearly or completely square.
The size of the patches can be related to the size of the particles - for a large, easy to see particle you can use a smaller patch. If you have a smaller or low contrast particle, you may get a better result with bigger patches. Any residual motion blur will act as an effective b-factor that can be overcome by averaging. I think 5-10 patches are all reasonable numbers that usually let something other than motion become resolution-limiting.