Capt PB
You've answered my questions on TCAS, so here are some answers for you.
On the Honeywell Global Express V7.0 installation:
We can display ABS or REL altitudes, though I've not run into anyone who does. Next I'm out in the plane, I'll try it and get back.
The neater part is that the RA is displayed on the PFD as "green" and "red" boxes, showing both pilots exactly where to put the pitch for the correct RA action. Very intuitive and simple; also reduces overshoots or too rapid reactions, just raise or lower the pitch to put in the box and "Bob's your uncle".
GF