My favorite Medium setup is:
Gerund AR- COGA/Greeneye Scope
- Muzzle Break
- Foregrip
Galactic/Kross SMG- YeoTek RDS
- Muzzle Break
- Speed Sling
- Extended Mags
Gerund has pin-point accuracy in short bursts which means you can do some good damage at mid-range, as well as it being great for hip-fire at close range or in CQC. It also becomes ridiculously potent when buffed... you can wind up doing anywhere around 80-180 damage PER-BURST, depending on how many bullets hit, how powerful the Engi's buff is, whether you 2 or 3-shot burst, if any were headshots, etc. The Kross/Galactic can be swapped to REALLY quickly and are both accurate and stable, with huge ammo capacities. Basically; go Galactic for more ammo + stability, Kross for more damage + accuracy.
Good for long/mid range support. I use the normal magazine, so I can get the most out of its stability. I usually don't fire this gun fast enough to make use of the rapid fire anyways.
With the standard mag, the Rokstedi fires faster than what it takes for the spread to settle anyway... spam the trigger and bullets are flying EVERYWHERE. Makes Rapid Fire kinda redundant. Gotta say, I've been warming up to the Drognav as an alternative to the Rokstedi... fires quicker and deals a LOT more damage, you just have to deal with the trade-off of low ammo capacity and reserves.