Ahh. And inverter Welder. I was thinking is was a VFD inverter.
anyway that aside you will need to make a box with two switches and run a 4 way cable, preferable screened back to the Welder.
then you'll need to trace back the tracks from the swithes to something you can solder to. I suspect that thet are membrane switched and therefore won't like a slodering iron next to them. onnce a suitable place is found the new switched and be put in parallel to the originals and youll be able to up/down remotely.
To be honest it will be alot of faffing around for something thats going to be a couple of meters from you and you usually set the amps for the rods you are using, so I cant see any advantage in having a remote.
There is a guy in the states that makes wireless controllers with a thumb wheel 3D printed on a stinger housing.
Got a 300m range
Ahh. And inverter Welder. I was thinking is was a VFD inverter.