Doug, I had crazy chine walking but solved it by putting a sleeve/spacer in the arm that goes from the end of the rack and pinion cable to the outboard motor. I deteched play by being able to move the outboard motor from side to side. This spacer tightens up the steering system. Also on my boat, my 2-blade bronze props are not lifting the bow like your Lightspeed or SRX are doing. More of the boat is in the water. If I elevate the motor 1" or so, than the other props I have come into play - the 22" Ballistic and the 22" Mercury Chopper, the equilent to your SRX. A Laser II 22" is also a possibility, the equilent to your Lightspeed. The PowerTech PTR 21" I tested this last week is a lost cause and will be sold or returned to the place that sold it to me on an exchange basis. Propably get a PowerTech RED 3-blade 21" prop with far less rake.
David