I'm sure exactly what the DR is on aura, shield, and barrier, but I'm guessing it's something like 15, 15, 40, respectively.

I say even out the DR these give you making them all even, making them all be like 20-22 or so... so they're all separate spells stacking up to 60%-66% redux.

Then all mages would 90% of the time have around 40% DR which is nearly perfect, and leave sleeks in the game with all the locations in tact as of right now. And the small chance to have all three spells at hero being around 15-20% chance.

Sounds like a pretty nifty system to me while keeping in tact the searching for wands so that you can attempt to have all three up all the time if you so wish to put in the time to search for your sleeks.

The only thing that would need a solution is the abundance of non-sleek abs perhaps if the imms think it's too abundant to fit into this system or not, which I'm not really so sure about from a balanced IMM perspective.