In GURPS Dungeon Fantasy/DFRPG, there's at least one spell offered to Clerics (even with low Power Investiture, meaning it's available to Henchman level or Priest lens characters) that has a relatively high casting cost: Final Rest at 20 FP.
A low point total character (say, a 187 point Ally, never mind a 125 point Henchman Initiate), or a character who has multiclassed by taking a Priest lens on top of another level class) would be unable to cast this spell without drawing a number of hit points to power the spell (in my case, with a shaved down Cleric template, I'd have to use 7 HP). The skill penalty of -1 per HP used to power a spell means this reduced-point character would be casting at effective skill 6 -- not a recipe for success.
A large enough Power Item to avoid drawing HP would, at the least, require either spending on a Wealth level or spending a one-time point for starting cash, and would still be one use between returns to base to have an NPC recharge the Item. Casting as Ceremonial Magic, requires Skill 15 and either one or more partners with the same or higher skill (requiring duplication between two healers, in my case), or a congregation large enough to do the job by contributing 1-3 FP each, depending on their abilities -- and that's a bit of a problem to travel potentially weeks from home base with.
My GM has suggested using paut (a potion found in DF:1), but as I read it, that only replaces spent fatigue, rather than letting the user store up FP prior to a casting.
What's the most effective method for a sub-250 point Cleric with neither traveling congregation or same-spell, same caster type partner to cast costly spells like Final Rest?