VS cabs have a horizontal monitor, those DK boards need a vert monitor. It would be a super pain in the ass (impossible?) to tate a VS monitor without some severe modification, he'd be better off just buying a dedicated Donkey Kong cab.
I know of some people that sell Multi-Jamma harnesses, but DK, DK JR and DK3 are not Jamma. I'd be curious as to how you propose he wire them all simultaneously. I guess you could make your own connector, but you'd need a decent amount of wiring knowledge that I personally do not posses.
Keeping it as a VS cab will give you a ton of options when it comes to board swaps, that's what I'd do at least.
Last thing, that cab looks like its in REALLY nice shape, right down to the T-molding. Excellent pick up my friend!
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