I hope you are dealing with a very experienced engine reconditioner, i have welded heads before with electrolisis in the coolant galleries having reconditioned engines for many years.
The electrolisis needs to be die ground out to clean alluminium before any tig welding is done and die ground again after to the correct port shape, before surface grinding. This is straight forward.
The issue that i must point out and hope that you have had a top notch reconditioner perform the task is the distortion that occurs during the tig welding process. Your head WILL be distorted after welding and MUST be straightened before surface grinding because the cam tunnel will also be distorted! If they have not straightened it before surface grinding the cam will not run concentric with the cam tunnel bores and will not have have any oil clearance and will wear the bores possibly even enough to cause it to lock up! This in turn strips the cam belt at the crank shaft gear and lots of bent valves are the result aswell...
I dont mean to scare you it may be fine aswell...
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