I have a Zaon PCAS mounted in my glare shield.
I have a couple of pictures showing the mounting configuration in the top of my glare shield. I didn't want the whole instrument sitting on top of the glare shield so I made a canted mounting so the face of the instrument shows.
I don't have a good picture of the final PCAS install but you can see it in the picture of my finished panel.
I don't have a picture of the PCAS antenna mounting, but I used a blade type DME/Transponder antenna for the PCAS. There is a minimum recommended distance it must be placed from your transponder antenna. I use the bulb type transponder antenna mounted under the passenger side of the fuselage and the PCAS antenna is mounted back under the baggage compartment so as to meet the minimum separation distance required.