What makes a P90 sound like a P90 is largely due to the form factor.
A P90 in humbucker form is a unique beast all its own with some P90 flavor.
I have a Fender Performer partscaster with a Humbucker sized P90 in the neck, love the tone

Toneshaper electrics, 4 way switching, Seymour Duncan Phat Cat P90 in the neck and a Seymour Duncan Alnico II Pro in the bridge.
^^^ THIS has been my experience. HB shaped "P90"'s have not sounded like P90's to me.
TV Jones makes the T90 that is supposedly good. But that's one I haven't tried.
A genuine Gibson P90 can be made to fit a HB space, but it's risky. I did two years ago and one I ruined. So 50% loss rate. The windings end up almost exactly the same size as the trim ring, so you risk abrading the winding wire. If you are mounting in a pickguard instead of a ring, it could be easier.
I cut and bent the brass base plate to match HB adjustment screws.
Drill and tap the screw holes in the brass plate.
You need to find blank covers with no holes and drill your own to match P90 spacing.
Here's a pic of one I modded (I just had a funky cover when I took this pic) :

BUT, on your archtop, you may have other options if there is room under the strings. I did this on a Gretsch I had by just putting p90 covers on top of matching pickup adaptor plates bought on ebay:

Here's the jury rigged version:
