Typically, early on, running 1 SSR defender weapon (that also has decent stats to function as a stat stick too) in your grid is okay for the extra HP until you can cover it with raw stats from an ssr grid. However, I really wouldn't recommend 2, as that would have a much bigger impact on your damage and doesn't give as much due to diminishing returns. This is mainly why people love dual skill assault/hp weapons, they fill this spot perfectly without a lot of drawback. So if you have tsuku's bow, just use it (it's not pure defender).