cheers for the comments guys.
chainstays; no problen, under tension the chain lifts off the stay, so no problem there!
chainline; as with many other lowracers i`ve looked at, chain runs past tyre, so there is a little rubbing on tighter corners, but i`m learning how much, so not a prob either!
front idler; tried it without, but having both power and return chain hitting the wheel, and turning, didnt work so well.
circuit racing i can drop it, less of a prob there. on the road, this seems to be the best configuration.
i`m 6` 2", so i need a little length there, lol!