mechanical brake on front wheel only????

I've convert my Mugen mbx5T with the RCM motor mount, but i want to keep the mechanical brake.
But i can't keep the rear brake rotor and caliper because the motor hit it, because i must run a 15T pinion.
So what i want to do is to keep only the front mechanical brake, and put an heavy fluid in the center diff, maybe 100000wt or something like that.
I know i'll have lot more brake on front and very little on rear, but what do you think of my setup guys?

Thank you for your help!

David