Nice idea!
But theres an issue with useabillity of it.
We can already get +20 or 30 max carry weight on ACTUAL armor that provides protection, so we would still aim for that, rather than something that gives +0 protection and +40 max carry weight at best.
Thats not all, these crafted armors can "also" provide bonus AP and bonus SPECIAL.
The bonus carry weight would have to be something like +120, to make it worthwhile, atleast somewhat, but even so, we are still better off, throwing infinite weight on a companion, whom are cheap and easy to acquire.
A simple solution could be, making it an off hand item, it would be "better than nothing" ya know but 40 carry weight is still underwhelming, thats like how much ? 30 wood/junk etc., something like +15,+30,+45,+60 and offhand item+rare/hard to achieve seems more practical/realistic to me (you know, am already a player who screws effectiveness over fun.. so you may imagine what pure meta players/tryhards think)
And whilst at it, I think the Binoculars should also give the +3 or 6, whatever it was, bonus, while being in the offhand slot, afterall you lose the abillity to put something else in that slot as backdraw.