1. There is a way of working out a SAM sites position if it is showing up on your RWR.
1)Put it in your 12 and create an overhead markpoint.
2)Put another markpoint 100 miles ahead of you.
3)Turn and put the SAM on you 3/9 line and carry on like that for a few minutes.
4)Put it back on your 12 and repeat steps 1&2.
5)Create a flightplan with Markpoints A-B-C-D. The lines will cross at some point on your TAD.
6)Slew the TAD cursor to the crossing point and create another markpoint.
7)Slew TGP to new markpoint, locate SAM and either engage or hide.
2. You can have a pre emptive flare program, and waste no time in breaking either way in your run if you get a launch. You can always strafe from a far way out with the Hog, you only need to get close with tanks.
EDIT: Like Razor said the A-10's strafed from 10,000 with a 60 degree dive. That's always an option and keeps you slant range short so it's still accurate.