havent really had issues with any of the hd geardifs ive put together. i did use some crc 30k lube on the orings and the outdrive sfor sealing purpose. sand the bottom of the gears so they fit in a little looser with the shims ect. maybe you have your screws too tight and compressing the gears.
turn buckles are indeed shorter, but when you upgrade to titanium, just follow the r1 standard. the r2 lengths are good for when you use the most outboard link locations on the inside though.
i run inside outer, and inside on the hub in the back. front i run middle/outer holes. my r1 turnbuckles were almost too long for the rear, but the r2 about perfect. in the front id run r1 length turnbuckles for sure.
chubs... honestly the old spec r parts are just fine. invest in the hardest front bumper you can and just try to hit less..I might try to get an NT1 hard front bumper and just trim it to fit 190mm. its wider than standard tc bumpers.
hit hard enough and any chub is gonna break. some people have used aluminum ones with success though.