To work out the distance of the inner edge:
I already knew that the inside staights are 85m and 2x85=170 the total needs to be 400m and 400-170=230 so 230m are curved. Ignoring the straight sections if the curves were put together they would form the circumference of a circe. The circumference of a circle is pi x D so 230/pi=73.21 2DP.and the diameter divided by 2 equals the radius =36.61 2DP
200m
1st starts 1/2 way around 1 straight and 1 curve
2nd starts 3.94 meters ahead about 6 degrees because r=36.61+1.25=37.86 curve circumference=118.94m 3.94 more than needed
3rd starts another 3.94m in front of them and so on
400m
1st starts on start/finish line
2nd starts twice as far ahead as 200m so 3.94x2 =7.88m
3rd starts 7.88m ahead of them and so on.