Modified the build a bit. Removed Hover (might put it back in after 50 as it's a prime slot for a Luck of the Gambler), which allowed me to take Voltaic Sentinel. Then re-assigned some of the endurance reduction slots from a bunch of the low endurance toggles (such as tough, weave, etc.) to allow voltaic sentinel to gain a full 6 slots. That does increase the endurance drain to 2.4/s, but it's still under the recovery rate of 3.8/s - also, there are a bunch of Elec powers slotted for endurance modification which should also help keep endurance topped up (guessing at this point, as this is now more of a theory learning build for me).
Final change was to move some of the powers around. A lot of the damage skills were being taken way too late in the build, so they have been moved so they are taken earlier - a bit of a trade off as some of the utility skills (tough, weave, hasten, etc.) got pushed back to later levels. The defensive powers also got a little more spread out and moved around (alpha barrier, fallout shelter, and proton armor specifically). My reasoning being that a dead enemy is no threat - so I'd rather have the offence earlier and live on the edge a little.
Dunno, think this is what I'm going to go with and give this a try - looks semi-solid on paper for an IO build. Plus, it will allow me to try out and play with all of the powers from both the primary and secondary tree. From there I can decide what powers I like, what I can live without. The only other thing that I'm not quite certain about is endurance usage - I may end up slotting more for some endurance reduction instead of endurance modification, but until I play it, I won't know how bad the sustain is.
Cheap IO Sentinel v2 (Electrical Blast - Radiation Armor).mbd