Next mod needed to cure the birds nest effect. Use steel liner all the way back to the rollers, ground into a " < " shape, and I mean all the way back to the rollers.
Did this on mine, never had a problem since. Previously I had to rebuild the thing after every 2 inches of weld.
Edit: I don't really mean 'all the way back to the rollers', as in don't have it touching / chaffing, but as close as you can without that happening.
Birds nest effect is literally impossible if there's no space for it to occur. Now I sit back and wait for someone to achieve my 'impossible'!