i haven't done a spine/regen scrapper since instant healing was no longer a toggle... but i do play /regen a bit and have solo'd EBs. i don't think you can solo an AV with Regen but on a team you should do fine. i use the combo of Instant Healing+Dull Pain+Resilience+Tough and sometimes +Wedding Band temp power to solo EBs. i also use IO sets to increase my regen and the recharge of my heals. i think using spines can help a little since it's supposed to -recharge, but i wouldn't count on it too much.