I don't think there's anything wrong at all with the stock ground clamp. It's as good as any I've seen on a stock welder, and better than some.
A "ground hog" or magnetic flat panel ground is somewhat specialized and specific to the application. If I did that sort of work, I'd just put one together with whatever length of cable needed since it's a QD dinse connector, not a hard connection inside the welder case, as on some welders. S/F....Ken M
Lincoln Power MIG 300
Everlast 160STH
Miller 225 Thunderbolt (sold it)
Lincoln Squarewave 175 TIG(traded it for)
Miller DEL 200 welder/genset
Thermal Dynamics 1250XL plasma cutter
Miller XMT300