There is much wisdom in those answers here. THANKS for sharing! So, from your helpful comments (on GTA and AGN), I come up with this summary on FFP's:
About the initial question in the OP: The reticle lines in most FFP's are usually not "too thick" (a few black sheep are out there, yes).
Rather, FFP reticle lines maintain the same thickness in relation to the objects we aim at, no matter the magni.
I DON'T NEED FFP — IF: If I only(!) do target shooting at known distances.
If I never(!) shoot with holdoffs, instead I always dial my turrets.
If I never(!) change the magnification of my variable magnification scope.
If I shoot with holdoffs, but I holdoff not in moas or mils using the reticle, but I hold off in inches at the target. (E.g., I hold 1/2 an inch above the squirrel's head to correct for pellet drop, instead of 3/4moa on the reticle.)
If I just prefer SFP over FFP, and that's that, period.
I LIKE FFP — IF: If I'm hunting or shooting at changing ranges using holdoffs — because I only need ONE range card that applies to any magnification I happen to chose.
And because I only need to memorize ONE set of holdoffs that applie to any magnification I use.
These data (memorized, or on a range card) apply to BOTH shooting with holdoffs and shooting with turret dialing.
➔ SO SIMPLE!
If I want to use the reticle for range finding — because I can use the hash marks at any mangi., no math needed.
If I shoot.... and then see how far I'm off target.... and measure that with the reticle — I then can dial the moas/mils that I'm off target and dial that correction directly on my turrets, no math needed.
FFP Disadvantage: The size and distance between the hash marks becomes smaller when the scope is at a lower magnification — and can become so small as not to be usable for holdoffs.
➔ But this does not always apply: This effect usually only applies for scopes with a large magni. ratio. 4x ratio seems to be fine, 6x ratio not so much. E.g.:
•4x ratio as in 6-24x | 4-16x | 3-12x | 8-32x
•5x ratio as in 4-20x | 3-15x | 5-25x
•6x ratio as in 3-18x | 4-24x
➔ To offset this disadvantage: —Usually I use a low magni. for close range shots — when for many gun/pellet combinations the holdoffs are very small, I'm usually in my point blank range.
(Sure, really low powered guns, or very heavy projectiles, or very high scope heights still will require large holdoffs even at shorter ranges.)
—I can use the reticle ilumination to make the reticle hash lines better visible; most scopes have IR, I might as well use it.
THANKS A LOT! Matthias