Adding capacitance

[mike 109444]

Not much room in this mig now for another inductor but have had a play with separate inductor coil in the past but didn't notice much difference to be honest .oh I do like making a silk purse out of a sows ear lol may be I will get a porta mig off santa this Christmas not long to go.

Well the guy had it outside of the mig (almost as a detachable/add on box if I recall). Could insert between the ground socket and it's lead.
Other ways of fiddling is with the input side of the main transformer. If you do a search for buck and boost on the forum and google you should find some clues. I know norrmspanners has had to fiddle with that to sort an issue with mains supply.