Just wanted to thank you guys for your input ! I read all the posts and tried out some loadouts while farming NPCs.
Slightly off topic : The first thing I notice is that dual ECCMs are pretty much worthless. I think it's strange that I keep getting serially jammed even with dual T4 ECCMs. It does prevent some jam attempts, but not enough to justify dedicating two head slots, not even close.
So, I tried the sensor amp approach --> dual T4 sensor amps on my RivelRepper. It's very annoying to be jammed so frequently, but at least I can lock quickly and get some volleys off with the advantage that all my head slots are dedicated to missile tunings. Plus, standard aggro management applies, like only lock one jamming type bot at a time, and deal with adds as they lock on.
More on topic : Using 1 universal hardener, two active racial hardeners for primary and secondary DPS types, and a medium plate, my RivelRepper has no problem keeping up with DPS even with 6 Hero Berserkers firing at me simultaneously. On purpose, I wait for the spawn to produce 2X triple packs of Berserkers and I'll aggro all of them at once. My health bar hits 50% but by then the non-primaried NPCs get bored and disengage. Bottom line, this set up is handling terrain spawns just fine.
So, I'm saving up EP to get my DPS higher before I take on a max beacon. I did some wimpy beacons as a test and I don't think the broken aggro triggers apply to beacons the same as for terrain NPCs. For one, the RivelRepper is targeted by the initial wave, but no subsequent. Then, the attacking NPCs do not disengage, so there is a need to recovery max health between waves. I'm not 100% I'm can do this solo and/or at current DPS capability. But fortunately, my extensions are far from maxed out, so I have plenty of DPS and Armor skills yet to be applied.