I've also been experimenting with several of the fluorinated amphetamines lately (every now and then, not daily use by any means), namely 2-fa, 2-fma, 4-fa and 3-fa, and various combinations of these.
In my experience 2-fa is definitely the most forgiving of these in terms of after effects, closely followed by 2-fma. 2-fa at around 20mg orally is great as a performance enhancer for me, or to help you get through the day after a night of too little sleep.
2-fma has more recreational value though and I definitely prefer this one for parties at around 60mg orally (~65kg male, mid 20s). I'm a pretty introverted person usually, and wouldn't normally enjoy parties with loud (not too good...) music and lots of people that much (especially when there are mostly people I don't know..). With 2-fma I enjoy it quite a lot though and will find myself talking with various people throughout the night without any of the awkward silent moments that would probably occur otherwise haha. Plus, because of the near absence of after effects I don't have to worry about performing badly at work either - at least at this dosage on a friday or saturday night (redosing once at 60mg at around T+6h doesn't seem to make this any worse either).
At higher dosages and/or repeatedly redosing (e.g. 2 day binges / 250mg+ sessions) there (unsurprisingly) is a definite amphetamine-like hangover though - for several days I'll be unmotivated, tired, find myself wanting to go to bed at 4 or 5 in the afternoon, and I'll sleep a lot more (can easily sleep 10h or more a night). Considering the amount of abuse these after effects are still quite mild though in my opinion.
With regard to combinations, if I want to give it little more of an mdma like feeling I love adding a low dose of 4-fa (also 60mg orally) to the mix! There seems to be a great synergy there. At this low of a dose (4-fa), the serotonin-depletion hangover effects are also very mild, but there might be some slight depression 1 or 2 days after use. I'm very sensitive to the "serotonin hangovers" though, which is also why I usually avoid any serotonin depleting drugs, unless it is a very special occasion and I have plenty of time to recover from it. I do like the mdma effect a lot more than the pure amphetamine effect, but the hangovers are usually not worth it for me.
I find 2-fma also combines very well with alcohol, as long as you stay responsible. Don't drink more than you would normally do without any stims. Here there also is a great synergy though. With mdma I completely avoid alcohol because in my opinion it ruins the high - I just get drunk instead of having that amazing mdma feeling. I'll never understand people combining alcohol and mdma. Some alcohol with your 2-fma, though: amazing! I think someone else mentioned it as well, it will almost immediately flush your face. Even only one mouthful of beer will send a wave of warmth over my face. It's great

But keep it safe.
Any other combinations didn't seem to stand out much. I have on occasion used very low doses of 3-fa (~10mg insufflated) in combination with 2-fma, 2-fa, and 4-fa which gives me a very short (~1h long), very dopaminergic mild/moderate high. This can be nice if it is something you are looking for but it's nothing too special. I've used it a couple of times right before taking 4-fa to bridge the time it takes for the 4-fa to start working, which can take up to an hour for me on an empty stomach.
I always have some etizolam on hand by the way to help me get to sleep after a night out

Especially with these long acting stims like 2fma and 4fa it's a huge help, and a good night of sleep helps a lot in preventing after effects. Any stim user probably knows this but I cannot recommend it enough.
I am a little curious regarding my usual 2-fma dosage of 60mg by the way, as this seems to be in the 'heavy' range? To me it doesn't feel like a particularly high dose at all, not by any means weak either, just a moderate to strong dose. Are those who report using it at around 30mg looking to use it primarily as a study aid?
Recently the place I get my RCs also has 4-fma now. I haven't read up on its effects much yet, but I have a feeling it might fall somewhere in between 2-fma and 4-fa effects-wise. Seeing as to how that combination is pretty amazing imo, I'm pretty excited to try this new little chem!