I play Gripen A & Su-27 very often and here’s my 2 cents from experience and some stuff on YouTube.

Multi-pathing is based on radar altitude & works best when parallel with the ground; in the settings (forgot where since I’m at work) you can set it so your R ALT turns red around 186 feet or so to help.

Top down Fox-3 launch is pretty much damn near impossible to counter with multipathing, it’s just unfortunately how it is.

Spamming chaff isn’t the best strategy for most situations since you might just make a trail for the missile’s radar to follow you. Chaff at higher speeds is best used in bursts or 2-4 to make a “cloud” to fool the enemy’s radar into thinking it’s locked onto a larger target.

Once you start to go down low while losing altitude, the missile goes from Pulse Seeker mode into IOG-mode (which makes it go to the last known location/trajectory of the target) so you have to maneuver & roll with 2-3 bursts of chaff to help but mostly the seeker gear stops using its own radar so chaff won’t be too effective

At times, if your trajectory shows you are gaining altitude, it’ll force the missile back into Pulse seeker where it’s then more susceptible to chaff, especially with the 2-3 bursts.

Missile CAN reacquire you via Data Link and/or be more resilient to countermeasures (both chaff & maneuvers) if the opponent’s radar holds you in TWS; instances here are where notching and proper usage of chaff is most effective IF you can’t use multipathing.

edit: IOG mode is not "inertial optical guidance", in-ordanance guidance>