Re: 72 Montgomery Ward Sea King
+1 on what was said above, if you are attaching X to the hull or through the floor. If you are mounting to your stringers you could use standard aluminum rivets.
Show us what your doing or thinking of and you should get some feedback.
Is yours a 12' or 14'. I had a 12' Sea King and the weight capacity was 560lbs if I remember. 2 - 100 lb kids plus me, motor, fuel, trolling motor, battery and gear and we were close to the limit. I am finishing up a 14' boat now, weight capacity 765lbs.
Don't know how big the live well will be but it will add a lot of weight. Add that to the fuel tank and motor all at the back, plus you operating the boat. Any chance to move the live well forward?
Carpet will hold water and be very dirty for fishing. If it's going right on the aluminum, are you just going to lay it in?
I saw a guy last week that had some kind of large plastic food trays for a floor. It was very nice looking. He cut them to size and trimmed to fit over the stringers. They pulled right out for cleaning.
Not trying to be real negative, just making sure you have thought everything through.
Let us know.