You know why AWD is good for soloing? It's not because of the 4set HP regen; it's because of the 6set that heals with dmg. If you really want some HP for solos and duos, then get the Lunia/Foriel set effect card. The HP regen isn't going to help much, if any at all. Like the HP increase, it'll help cushion maybe one or two attacks in myth, and that's it. Besides, there are people who can solo without any heals.
I would take off HP increase, enhance survivability, and Sulfur Rain for Max Iron Bomb, 1 left and right slide shots, and Max Rapid Rail Gun. Sulfur Rain takes a long time to cast, which can be a problem against unflinchable bosses. The invincibility frames from the slide shots will be useful in avoiding Foriel's attacks.