I was going to mount one of the Guild DeArmond reproductions on one of my archtops but really didn't want to drill any holes in the neck for the mounting rod and came up with this for attaching it to the pickguard. It's a first effort and I am sure could be refined. I'd welcome any suggestions or other ways you guys might have done the same thing.
Take a piece of 1/4" plexiglass and slot it on the band saw (1/4" blade). Drill mounting holes and holes for bolts to tighten the slot. (I used stainless 4-40 bolts and tap)
The tab on the pickup is a snug fit and can be stabilized by tightening the bolts.
Notch the pickguard and locate the pickup then drill the mounting holes in the pickguard and bolt on. The pickup can be slid up and down in the slot for position before tightening.
I used a piece of firm rubber to support the bass end. Only downside I see is that it can rotate but with the bolts tightened it is pretty stable. This is a nice pickup, I really like the sound. I am going to play out with it tomorrow, we'll see if there is any noise but at home it sounds great.