Before you could get custom bags made from wakemakers I was stuck with 3/4" fittings.
So I decided to add 1 1/8" fittings to my bags for a reversible pump.
I planned on using the flow-rite through hull fittings with RTV silicone added to ensure a leak free seal.
Here is the fitting I used. https://flow-rite.com/products/marine/1-18-fittings/ma-044-qlb
I hooked up a air pump to ensure it would stay inflated so I could work with the bag.
I then drew out the hole needed for the port to go through but left it a tad on the small side.
I then used a new razor blade to carefully cut the hole out.
I then pushed the mushroom end of the fitting through the bag after putting a liberal coating of rtv on the edge of the fitting that would mate with the bag.
Then just put the nut on and tighten down.
Definitely measure 4 times cut once. It was almost as unnerving as drilling hole through the hull.