Level 30 leve help

I want to start level 30 leves (@ rank 26) for guild marks. Are they possible to solo at one star?

Indeed. That is about when I started them. It certainly helps if you have a high physical level and/or other jobs from which to borrow skills (namely, Cure and Sac)

What level were the mobs? and is level 1 cure / sac enough?