One of the Fly Baby crowd put together a paper on the care and feeding of Maule
tailwheels:

http://www.bowersflybaby.com/tech/Maule_Tailwheel.pdf

He recommends dissimilar springs to discourage shimmy, and says that binding or
looseness in the assembly itself encourages it.

Myself, I haven't had a problem.

Ron Wanttaja

I have the 6" Maul on my Jungster II. To cure the uneven tire wear I
replaced the Maul wheel with one of the ones ASS sells for the
homebuilt tailwheel unit. It has a metal hub and has less tendency to
run over. You can frequently get the same wheel at a industrial wheel
supplier. Check your axle size as they come in two different bores.

Ed Sullivan