The omnibooster is a more elaborate version of a trash bag booster - originally described by Vance Harlow aka Oxyhacker
Too much work for me. What is your dive going to look like?
My O2 sense
Blend the highest He to the Lowest He and have your blender match O2 levels (hyperoxic) across the group, He levels won't be critical but need to be calculated.
PS: If someone came in my shop and asked me to circle jerk and bunch of mixes around my time would be more than dumping the mixes and going anew.
The OP is in New Zealand. If you paid his helium prices you'd investigate ways to recycle 11/89 too.
Plus prices for this non-renewable gas are climbing all over.