Wika/double bottle/Impact?

I put a Wika on my Wildcat. The old FX one was WAY off calibration :( :(
Anybody put a Wika on an Impact with the double bottle adapter? It won't fit unless the adapter is machined away for clearance...maybe an eight inch. Shouldn't hurt anything as it's pretty stout(?).....or, is the plug 1/8 BSPP?

Top gauge is off the Wildcat and just sitting there to show you what it is reading with no pressure.

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