I think it would be more like 15 feet per banking at Lexus, so closer to 1000 laps (which is still only 100 miles of course). It would be like 4+ hours on a roller coaster
The main problem would be getting your Garmin to record it properly - look at Strava files of rides at the velodrome and you see some very odd shapes.
Plus Hells 500 would probably say that the banking at the two ends of the track counted as 2 hills and disqualify you, so there's that.