I'm note sure on mileage but my twin 32/36 webers main fuel jets run 180's on the primarys and 220's on the secondarys at WOT. That's a lot of fuel.
The guys at the import shop had never ordered 220's and said they were surprised that they even made them for a DGV 32/36.

I did a track day yesterday and basically ran the car out of fuel 3 times and I also ran out just as I pulled the car back in the garage, it's likely a case of idiot me just not putting enough in but the mileage seems a bit high.

The 5 gallon cell was full to the brim, I did two 30 minute sessions and with about a minute to go in the second session the car starved out in a high G turn. I just made it back to my pit. It's a 3.4 mile course and I get 8-10 laps depending on traffic so that's between 54 and 60 miles. So I'm getting 12 mph tops and possibly as low as 9.5, does this sound about average. The showroom stock Miata I raced only managed 9 mpg so it's not unthinkable that it's this low.

Note this is an A15 with flat slides, 278 degree cam with .420 valve lift ported GX head 37/30 valves revving between 4800-8000 rpms making around 105-110 at the wheels.

Tom