help spell abjuration

Casting time: 12 rounds
Type of spell: defensive spell
Affecting stats: wis
Cast type: protection
Spell point cost: 100
Abjurers of old once dreamed about the ultimate protection spell, and after
centuries of research, they came up with abjuration. It has the intricate
framework to include all kinds of protections. Mages have learned this spell
in order to save their own skin, as well as their friends.

I was thinking that this spell could be cast so that you can add different
major prot spells that you know, ie:
cast abjuration at tyril with armour of aether,repulsor aura,flame
shield,frost shield,lightning shield,toxic dilution
The resulting spcost would be all of the spcosts of the base spells (with
appropriate reductions for power reagents or increases for poor reagents). If
you finish the spell and don't have enough sps, it's would be similar to
resurrect (as in let you start casting, but if you're short at the end, it
just doesn't work). Also it would make the spells all end at the same time
(either take the shortest duration of the combined spells or maybe an
average).