Great, don't give up now!
OK first a little sketch of how the offsets work:

You are right: first,
copy and paste the whole thing underneath, as many times as you want wingmen.
Let's have two wingmen, so paste onto the end twice, a total of 3.
Number the additional tracks, 2 and 3.
Then,
change the a/c name (use the "Title" from the aircraft.cfg file.)
Change the #StaticCGtoGround to match the plane (Look in the aircraft.cfg for "static_cg_height=")
Insert the offset line after the "timestamp" header:
$Offset: -30 0 15 for track 2
$Offset: -30 0 -15 for track 3
(The 0 is for zero height difference)
Save the file
Run ascii2frcDone!
SAMPLE// Track 1
#Aircraft: "Douglas DC-3 - Warbirds NZ3546 (flipped logo)"
#StaticCGtoGround: 9.9
#Data: latitude longitude altitude pitch bank heading onground velocityX velocityY velocityZ throttle1 throttle2 throttle3 throttle4 elevators ailerons rudder spoilers flaps gear lights parkbrake engine1 engine2 engine3 engine4 timestamp
-43.3691955048 172.7071076456 1608.905 -1.577 0.154 4.624 0 40.01060 -5.19030 274.81440 13081 13081 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0.0000
-43.3691135841 172.7071240228 1608.733 -1.575 0.150 4.628 0 40.03060 -5.16623 275.01645 13081 13081 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0.1681
etc etc// Track 2
#Aircraft: "Trolly's A/C No 2"
#StaticCGtoGround: 3.20000
#Data: latitude longitude altitude pitch bank heading onground velocityX velocityY velocityZ throttle1 throttle2 throttle3 throttle4 elevators ailerons rudder spoilers flaps gear lights parkbrake engine1 engine2 engine3 engine4 timestamp
$Offset: -30 0 15-43.3691955048 172.7071076456 1608.905 -1.577 0.154 4.624 0 40.01060 -5.19030 274.81440 13081 13081 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0.0000
-43.3691135841 172.7071240228 1608.733 -1.575 0.150 4.628 0 40.03060 -5.16623 275.01645 13081 13081 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0.1681
etc etc
// Track 3
#Aircraft: "Trolly's A/C No 3"
#StaticCGtoGround: 3.20000#Data: latitude longitude altitude pitch bank heading onground velocityX velocityY velocityZ throttle1 throttle2 throttle3 throttle4 elevators ailerons rudder spoilers flaps gear lights parkbrake engine1 engine2 engine3 engine4 timestamp
$Offset: -30 0 -15
-43.3691955048 172.7071076456 1608.905 -1.577 0.154 4.624 0 40.01060 -5.19030 274.81440 13081 13081 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0.0000
-43.3691135841 172.7071240228 1608.733 -1.575 0.150 4.628 0 40.03060 -5.16623 275.01645 13081 13081 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0.1681 etc etc