The MS can log fuel usage (and really anything else you want). There are a number of ways to view that data... laptop/phone/etc. Here's one to get you started.
msDroid :: MegaSquirt configuration and log recorder / viewer for Android If you check some MS forums, you may find some better options.
I love that you have the slant running with an MS. I started one as a project in the past, but never got too far. Had a '71 and a'74 Valiant. I don't think either of them saw any higher than 18mpg and any lower than 17mpg.