Alex, if you were to build one, i've got a spare bash you can mill down for me when you've perfected your design, i just might prefer a less holey design, have you used any computer modelled stress testing software to see what it can take?
Step one, man up and ride it.
Mine's fondling the other side of 12kg, gives me an excuse for being shit.
Step two, gettin better on this bike with all its drawbacks will mean after you've saved all the money you would have spent on parts you can upgrade the whole thing and you'll be way better due to the experience gained on the heavier bike.
to be honest you need to get to a ride and ask people if youcan have a go, see what's comfortable for you then you kinda know what to go for rather than just buying things willy nilly
A clipic is a moto trials bike, so someone might know on here xP
http://www.bshtuning.co.uk/shop/product_info.php?info=p2443_Carb-Amal--Arreche--21mm.html&XTCsid=ab5cd1826c583ca3efbc71052895691d
This should sort you out.