As I stated for OP several times bow must be built for certain power(read str requirements).
You can play with draw weight little by shortening or extending the bow string.
Heh, I now see you were the one who mentioned the min STR for weapons. I agree that approach makes the most sense. I'd forgo adding that level of detail at my table (If it were in the books, I'd use it, but I'd rather spend my prep time doing other things). As a mechanic I think it works well.