Yes, 100 miles per week including commuting, training and club rides. The rationale is to choose a cadence; 90-95 rpm, for a comfortable cruising speed, say 17 mph and that will give you the gear needed;
so 17 (miles per hour) = 90 * 60 (revs per hour) * XXX (inches per rev) /63360 (inches/mile)
XXX = 17 * 63360/(90*60) = 199.4 (circumferance)/PI = 63″ wheel diameter (this is the standard 42×16 beloved of all off the shelf fixed and SS bikes).
Gear inches are wheel diameter-equivalent so need a correction of PI, hence for 90 rpm, which is where you should be;
XXX gear inches = 3.73 * speed in mph
78″ (42×15) is a big gear for starting out and is really a gear for 20 mph rides. It’s my goto gear for aerobic threshold training and medium paced club runs. That said, I’m currently riding 42×14 or 84″ fixed for sprint and strength training and it is tiring grinding along at 70-80 rpm.
As an aside, riding fixed gives several advantages;
1) you will learn to spin like a god
2) you will learn to clip in like a god
3) you will develop leg strength and speed
4) fewer things to go wrong
5) cadence = speed = power (well a pretty good measure of it)
So for my training I use cadence as a power substitute – force is roughly constant when I ride (I do stand up a bit though), and hence power is proportional to cadence.