try disabling melee aims toward camera in settings, that will change your melee direction from your camera to your movement keys. this allows you to angle your melee attacks by attempting to move, very useful for rapier heavy attacks.
for frames, mains will typically have 6+ forma, my limbo has 8 and my yareli has 9. other frames you don't use very often might have just a single, or 2-4. exalted weapon frames will likely use 5-10 total, and sevagoth needs at minimum 13.
for weapons, favorites will, again, have 6+ forma. kuva/tenets get 5, no more since 40 capacity, and no less because of the extra mastery (don't go full 5 if you don't have a ton of forma though). weapons you don't use often may have 1-4. melees typically use less forma due to the extra capacity gained with stance mods.
ooooooh steel path simulacrum
time to test against enemies that don't die to my vectis in one hit lol
or... hopefully at least
incarnon soma, both the base and incarnon form, shred through steel path with ease
easily the best assault rifle right now
999 on my soma riven (cd/cold/-zoom) its pretty good but will eventually be even more when I care enough to keep going lol
basically doesn't matter, just use the ones you like the look of
soma, my favorite gun got turned into the best assault rifle in the game with an assault shotgun mode
tenet livia for toxin, and destreza prime with riven for max slash damage, if no riven, reaper prime
with destreza, disable melee toward camera in settings, then you can use the movement keys to hit multiple enemies during a heavy attack.