What should one expect to pay to have the hook built up via TIG welding, fitted, etc.?

I buy these old Husqvarna and Sauer hammer doubles to shoot and hunt with. I seldom pay much for them -- they were in some Swede's basement, barn, closest for decades before I get them. I try to find guns that need only cleaning, polishing, recutting of net checkering, refinishing of stocks, etc. Now and then I find one that needs work I cannot do, usually sears adjusted. This is first off-face one. Aside from being somewhat off-face, I am expecting this gun to be still another that I will use on many hunts for ducks, geese, quail, grouse, bandtails, etc., not to mention lots of rounds of trap and SC.

For next months I will be usïng tape, thin metal, or nothing, on hook as I determine just how good and reliable a shooter it is and what ammo shoots well in it. I am looking forward to seeing how much difference 80 cm barrel is over 75s I normally shoot. Then there is cylinder barrel -- have not hunted with a long-barreled, cylinder-choked gun in decades. Curious to see how it works on decoying ducks with Bi-Sn shot.

Thanks for all the advice and information provided here. Sooner or later, most (at least) will be useful. IF not with this gun, then another one.

Niklas