I will note it here in my hand little notebook that about 250ish is where the DR starts getting the better of Surge. I make my own augments (armstech) and will see what removing one does as they are +18 Surge and that will sit me on 250 even. If it is at 75%, I will call that my soft cap and move on to power or maybe even endurance augments. I have slowly been moving from Commando pieces to Reflex pieces as I advance at level 50 and tend to tank less for Mako than I DPS for a human tank.
As a side note, I got my first 1.5 "columi set" armorings. It's too bad that the armorings inside the 2 full pieces I have didn't bump up to them so I could pull them out and put them in something else and keep the set bonus. I really do hate that gear. LOL I call it my bagpipe/church organ/noodle-making machine set. If they would take those silly pipes off the back, I could like that gear.
EDIT: I have not been 50 long on either of my characters. So this is still really new to me with the modding. I acquired the armorings and barrels in Black Hole on Corellia really fast but the mods and enhancements have mostly been yanked out of the odd drops here and there. Your advice is very helpful!