Speedway Calculated Draw

We need a calculated Draw for speedway racing. Each driver can race a set number of races - known as Heats - Heats are divided into Rounds e.g. 3 Round x 3 Heats = total of 9 heats. Each driver races once per Round. The starting positions for each driver must equal to the optimum number.
Example - this is how to work out the optimum number
34 drivers - 3 heats x 3 rounds
2 heats of 11 cars and 1 heat of 12 cars
Add starting positions 1,2,3,4,5,6,7,8,9,10,11 = 66 x 2 = 132
Add starting positions 1,2,3,4,5,6,7,8,9,10,11,12 = 78
Total positions per round = 132 + 78 = 210
Total number of starting positions = 210 x 3 rounds = 630 divided by number of nominations (34) = 18.53

Each drivers drawn positions should add up to the 18 or 19 because of the .53 this should give a relatively equal split of drivers
If the number was even with no part decimal then all draws would be 18
If the decimal point was .05 then the majority would be on the one optimum number
Potential combinations could be:
Rnd 1 Rnd 2 Rnd 3 total
2 10 6 18
3 5 10 18
11 1 6 18
11 2 5 18
Each round having 3 heats can have 3 of each position with the total positions of each round = 210
The variables required to calculate the positions of each driver are - number of drivers - number of heats - number of rounds