I run Wiggs Fac Shore and Rex. I run Wedge lead due to TM gain on the cannons and for offence gain. Rex is there to thank people for giving me a negative effect e.g. B2 or oppositions Wedge, neuter Palpy and I run him at 240 speed to get Shore and Fac quick off the mark. I've tried them both at lead and this is a personal preference.
It comes down to the speed of your team and who is going to protect you in the opening 'crits' you receive. Many people go for a Rex lead. Personally I prefer hitting harder in turn 1, and not being reliant on crits landing on me to boost some TM. Kinda doesn't help I run Shore as when crit immunity is up..