If it helps, this is what the spells summon in pnp:
MS I: 2d4 1st-level monsters for 2 rds. + 1 rd./level. Casting time 3, area of effect 30-yd. radius
MS II: 1d6 2nd-level monsters for 3 rds. + 1 rd./level. Casting time 4, area of effect 40-yd. radius
MS III: 1d4 3rd-level monsters for 4 rds. + 1 rd./level. Casting time 5, area of effect 50-yd. radius
MS IV: 1d3 4th-level monsters for 5 rds. + 1 rd./level. Casting time 6, area of effect 60-yd. radius
MS V: 1d3 5th-level monsters for 6 rds. + 1 rd./level. Casting time 7, area of effect 70-yd. radius
MS VI: 1d3 6th-level monsters appear 1d3 rounds after spell is cast for 7 rds. + 1 rd./level. Casting time 8, area of effect 80-yd. radius,
MS VII: One 7th-level monster or two 7th-level monsters appear one round after spell is cast, or one 8th-level monster appears two rounds after spell is cast, both for 8rds. + 1 rd./level. Casting time 9, area of effect 90-yd. radius
So it doesn't really matter which monsters are used (though IIRC they have to be living & breathing monsters from the current plane of existence, so no elementals, golems, demons, celestials, undead, etc), as long as they're the appropriate level
.