Hey Chris,
Brett05 and I have been comparing notes on shudder reduction. I went down the track of new tail shaft with slip joint and centre bearing, Brett made some blocks that will lower the centre bearing height. You seem very handy so harass brett to make you some blocks to improve the angle and reduce shudder. I still have a little shudder but it is managable. One thing to remember which really amplified my shudder is to check the shackles are tight and retighten them after 1000km becasue this helped in my case.
Mitch