If the problem is only with standby-resume, I doubt changing cluster size would do you any good. Larger than 4k clusters mean you can't use NTFS compression, but other than that there's not much downside - perhaps even upside since file fragments get larger, and you thus get slightly less fragmentation.
Standby can, unfortunately, give a zillion problems. Usually driver-related hangs though, dunno why it would mess up VSS :-s