[thejeff]

Akashic record is rarely used in MP. It's too expensive and comes too late.

Lack of Astral is a problem, particularly since it's hard to bootstrap. There are no cheap low-level Astral mages to summon for site-searching & routine forging. If you take a rainbow pretender, send it out manually site searching and hope for either Astral indies (lizards!) or you'll probably need to wait for spectres or empower for other astral mages.
I probably would take an Astral Rainbow, if only for access to RoW/S.

By the time you're fighting mostly demons and other summons you'll have your own. Undead thugs and, in CBM, drakes. Spiders remain useful until the big MR-resist spells come to dominate the battlefield, but they're not your only tool.