[Varyon]

Perhaps a leveled Perk would be more appropriate? For the first level, you'd increase your max to 5xMinST, the second to 7xMinST, then 10x, and so forth, following the Size and Speed/Range Table.

Given you're only using this to allow you to get full effect out of Power Blow, and not so Superman can decapitate Godzilla with a kitchen knife, I'd probably allow you to just ignore it for purposes of Power Blow with only a single Perk - the above would be more appropriate for being able to exceed it in general use. Alternatively, see if he'll allow you to get weapons made out of some sort of unobtanium that are more resilient then normal (the general justification for needing to limit yourself to 3xMinST is that attacking harder than that risks breaking the weapon).