It's all a good plan... except the weber.... twins/sides/down draught... none of them hold their tune for more than 6 months, and they need a full rebuild kit put through them (the diaphragms fall apart and gaskets leak in that time) i don't think a good kit has been made for them since the days of good ol' asbestos but i could be wrong
even the standard carb needs tuning for hot weather vs. cold weather... but thats just an adjustment on the screw not a rebuild
I've had nearly every motor combo in a 1200 over about 13 years and i stand by the GX carbs (twin side SU's) especially for street
I run them on the rally car because the low end power combined with top end makes it so drivable you can throw the car around however you like in the right or wrong gear and trust it's gonna be able to pull you out of a slide (and nobody believes we have just an A14 in it when they see our results)
webers are nothing but top end power and require you to drive like a flog on the street. carry a fire extinguisher if your running twin sides!
i could go on but thats my general point of view. it will be fun either way but dare to different to the "put a weber on it" trend!