Comparison… is it worth the bother?

So – I now have my 'Conda the way I think it SHOULD be, based on our earlier discussion about shields and so on.

So – here's my current ACTUAL build: EDSY "Material Girl II"

and here's how it WOULD be with bi-Weaves and the same engineering : EDSY "Material Girl III"

My question now is: is it worth all the bother of re-doing the engineering? Or is the difference small enough that I don't get much for my work?

Second question: do I need more weapons? I don't get any PvP in my day-to-day, so it's mostly a PvE craft which is a VERY defensible trader/mission runner. I now have 4 empty slots and no idea what to do with them…