I think I might rework substitute instead, seeing how it really only has 1 use case when your number is really low. I'm not sure there is a way around the hp cap though, since the math gets harder when the numbers hit 3 digits.
To be honest the cap stops you getting *too* powerful at least, and 3 digits would be a bit squashed (plus you can still drop down by a lot with mismanagement >.>)
