I farmed up the duck hats needed to buy the shock mods and the sniper rifle last night, I still need to do the archwing weapon, but I have time for that this morning.
The shock dual-stats are the best items he has this time by far. I finally have all 4 shotgun dual-stats, which means I can finish my 100% status Sancti Tigris build. Basically it isn't much different than it was, just with 2k more radiation damage.
Just to put the finishing touches on the day, I did an Arbitration and managed to not only get a over 6k endo, but a statue and (drumroll) Adaptation. My Umbral Inaros has now officially reached silly levels of tankyness. To make things even better, I slotted it into my Gara build as well. TBH she really doesn't need it, but 90% DR from her 2 stacked with up to 90% DR from the mod should make her tankiness also reach silly levels. For now I dropped Augur Reach (I think that is the right name, the lesser range mod), but I need to look the build over again. Range is really important for Gara, albeit a little less so than duration and efficiency IMHO. She really needs a few more forma.
While farming duck hats I blundered into the last Oberon Prime and Nekros Prime parts I was missing. I never did a proper build for either, seeing as I refuse to waste potatos and forma on non-prime frames, but my Nekros was already pretty tough. I'm pretty sure I'll put Adaptation and Health Conversion on my proper build, which should make him into a solid tank as well. A tank Nekros could be useful in Arbitration survival or any number of other missions where more loot would be useful.
To make a long story short, I had a very productive day of farming.