Depending on the age of the Strat Plus, the body will either have HSH routing or one big rectangular "swimming pool" rout, so it's OK for humbuckers.
I'd get humbuckers with short legs, or the routing might not be deep enough. And to be 100% sure, use a genuine Fender scratchplate - if you get a generic one with the bridge humbucker very close to the bridge, it may not line up with the routing.
