There are very few things I won't do myself on a lathe or mill but porting a barrel, especially as precision as a match target pistol is one of em,

Any machining method is likely to leave a burr that will effect pellet stability, also you need to ensure the holes are in the rifle grooves and not the lands, This would taken some very careful maths (something i'm sure your capable of) and also some VERY precise machining, the space in the grooves is very tight to the size of holes needed to make the porting effective, EDM would I think be the best method if you were to go ahead.

Machining an alternative and already ported barrel from another supplier to fit would be an easier option. (lp10, lp50 etc)