Hi, I had a big-long reply but I accidentally deleted it 
Anyways, I created an inventory system that is weight based here (look for the update at the bottom): [Resource] Please Break/Test/MakeUseOf my "Simpler Inventory System!"
It’s SUPER complex though.
Make sure you subtract the weight you added if it is over your maximum weight amount, or build in a mechanism to check for overencumbrance before adding weight.