Sorry to say but I think you are dead wrong on the need for high airflow on the rotary and there is no way 350 CFM will work unless you want to fly a turd.      

Fair enough.  I can certainly agree, to disagree.  I'm not sure which Ellison you're referring to, with the 350 CFM number, but I would absolutely bolt an EFS 4-5 to a NA 13B in a heartbeat.   

You did a fine job making that high flow manifold and I bet you wont put a 350 CFM throttle body on it. 

TWM doesn't publish CFM ratings that I know of, but I got a TWM 3000, with 55 mm bores.  The ONLY reason I got that size was that it came with dual fuel rails, and 4 injectors.  I was really tired of not having matching injectors. 

 For anyone thinking of a Weber I will say there are pros and cons between a 48 and a 51, the 51 puts out more power but it is temperamental on jetting and it runs rough on the bottom end compared to the 48,

This is really the classic hot rod carb theory.  Put a 1050 Holley double pumper on a chevy 350, and it will have the best possible WOT power, but drivability will suffer, since it's too large to precisely control the low throttle requirements.  Put a 600 on it, and you'll lose a tiny bit of high end, but gain throttle response everywhere else. 

All that being said, I can't help but agree that we care more about high end, than low and mid range throttle.  Still, I think the Ellison would make a fine choice, even if you get one of the "too big" sizes. 

Rusty (my 4A084 won't have EFI or an Ellison)