But of a min-maxing question really but this doesn't make sense to me. I get +1 from human form no matter how many powers I link it to. The "best" way to do this is have it link to the least usefull power or power which would be least affected. Like:
Beast Change [-1]
- Human Form [+1]
Inhuman Strength [-2]
Inhuman Toughness [-2]
- Catch [+1]
for a total refresh cost of -3.
[edit typos]
You can't link the human form only to beast change and still get the rebate. You can never reduce the cost of a power to zero through rebates.
You
could however, restrict just the Strength with the human form, which means he'd only be stronger when he's full-bodied beast, but still has the Toughness when human.
Or you could increase his toughness by a level and then apply the Human Form rebate to that in conjunction with the catch.