I usually burn about 200ml at a track day in an engine in excellent condition. I used to burn more until I started only filling it to just 3/4 full and checking after every run or two instead. It might be worth making sure that you've got the right length dipstick in your car. Nearly every MX5 dipstick known to man has been broken and some have been replaced with a wrong one.
X2 with jbt. 10W-50 Penrite HPR10 FTW.
NA8 daily driver: sorted suspension/brakes, old Loch Stewart CAI, T&C exhaust, torsen, COPs, re-route, seat time
SMPGP 1:55.048 : Wakie 1:12.11