Reasonably speaking, I would think Fuel injection would be the best. Lectron's have been around for a long time, Are they the best, who knows. The new PSI carbs look promising, a few more adjustments than the lectron and all external, easier needle adjustment. And as an added bonus they are bored like a triangle small at the bootom and large at the top, supposed to respond like a stock carb at low end and like a big carb on the top end. In my sport there are alot of guys using the lectron, they work.
By the way I didn't know the XL series had a standard length of 2.050, thanks for the update.