Originally Posted by
capwater
Get an SRAM or a mtb cassette, they don't use cog carriers and thus have cogs full begth with contact the hub splines. I'd stick to the same speed unless you have no other option just to be on the safe side.
Shimano 105-level 9 and 10-speed cassettes use carriers only for the three largest cogs so all of the smaller cogs are "full plate" and can be rearranged at will.