1- Both powerflarm antennas in the nose (no carbon in the nose section of my 27a).
2- transponder antenna under the seat pan in front of the stick (so not far from the powerflarm antenna, maybe 3 feet at the most.
3 - configuration file may need to wait until next week or so. BTW I recall there is an option to suppress own transponder more aggressively, I just used the default.

I really never had false alert from my own transponder, no kidding. And my mode C alert is working very well.

Ramy