Caswell Mfg (NY) has a line of brush plating kits in the $45 range incl gold plating kits. They work on the same idea as the Texas Plating Kit.
...if you're still thinking of going in that direction.
Plating Kits - Caswell Inc

The only plater I have ever used is Reliable Electro Plating in Chartley, MA.
I've always sent them the parts already polished and with instructions to do no more additional polishing. The plating has always been first class. Quick service. I've had nickle, silver and gold done,,complete handguns and parts.

Firearms Plating: Custom Metal Finishing: Reliable Electroplating: Chartley, MA

They do offer strip of old plating, polishing & replating service,, and they do have an FFL so you can send them a firearm no problem.
They ask that any parts be disassembled.

Quite a few gunsmiths & engravers use them.