That's great you found sprinting and even was able to find open track meets! My two cents into the subject. Last year I experimented with a month of 100m on the road and track, so when I started I ran about 13.85 for 80m, I didn't even know where the 100m start line was XD That's 16.62 if you multiply by 1.2 my 40 was 5.97. I ran that in 20min. 5k shape weighing like 158 at 5'7". A month of flying 60s, 150m dashes and even 200s and 400 for fun in the afternoons after morning distance training I was able to get down to 13.05. No blocks, but self timed in cheap ass "running" sneakers. I think my flying start 40yd was 4.25 at that time, and I got to 25:58 4mile shape.
Every healthy fit man i know could outsprint me though, even the obese footballers. That's your reference to who i am as a sprinter. I'm someone who's worked out since 16yr and came back from obesity twice and has seriously ran distance for two years.
40yd 5.97 to 4.98
60m fly 6.67
100m 13.05, so roughly 13.3
200m 33.xx at my peak 100m shape, but now 32 relaxed in a workout, so could be faster
400m 67-68 as of last year, I'll check in tomorrow for this time.