Replacing gate valve with proper seacock

On the left is a shot of the original thru-hull for my shower sump. It has a bronze thru hull with a gate valve. It is situated above the waterline unless you’re on a port tack then it’s well underwater. I don’t think it’s not up to code, but it made me squeamish so I am replacing it with a marelon thru hull and ball valve seacock.
There’s a great video on YouTube from Forespar about how to mount Marelon seacocks which I posted previously. I am basically following those exact steps.
1. I removed the old hose from the barb, the valve from the thru hull and the thru hull from the boat.
2. I then prepped the inside of the hull by sanding it down to clean fiberglass with a 4” Ryobi angle grinder.
3. I prepared a 1/2” marine grade plywood backing plate by cutting the wood and coating it with West Systems epoxy. This will be an upgrade over the original installation which has no backing plate.
4. Next I dry fit everything to make sure it would all fit together and be able to be tightened adequately.

From the originalGate Valve
.