Sorry for the not so quick reply. The problem with non-potatoed weapons, as you may have realized by now, is that the mod capacity is at a premium, and you have two ways to spend it: either install several lower ranks mods, or use very few but at higher rank.
I think it’s more optimal if you go for the second option. From this perspective, this is a possible build for your Latron:
Serration at rank 6, installed on the V polarity slot. You get twice the base damage per shot, every shot. I recommend you get your Serration to this rank as soon as you can, if you haven’t achieved it yet. For the time being, while you collect more resources, it should be enough for all your primary builds.
If you want to go for a crit build: install both Point Strike and Vital Sense at max rank. You get 25% critical chance, i.e., roughly one in every 4 shots will do x4.4 damage. You have 7 points left (considering a rank 30 Latron). You can equip a single elementary mod at rank 1 for an extra 30% damage of that type (the status chance is too low so we won’t consider the proc). According to Warframe Builder, every shot, on average, will deal about 271 damage points.
[*]The other option is to forfeit the crit mods and go for a combined elemental build. Again, two options here: two elemental mods at rank 3 (+ 60% damage each one), i.e., Infected Clip (Toxic) + Stormbringer (Electricity) for Corrosive damage, which is good in general, plus a third elemental mod (either Heat or Cold) at rank 1 (+30% damage); or, two elemental mods at max rank (+90% each), which will leave you 3 unused mod points. You can equip Fast Hands at rank 1 for a slight decrease of the reloading time, or rank 1 Ammo Drum, to increase the ammo cap with 54 more shots. The average damage per shot is 310 for the first option, and 347 for the second one.