I think the way you describe it would be better but we have gone with this for a while its 1 vote per 5 entrants rounded down. The overlap of about a quarter or fifth of the votes has broken some deadlocks in the past. When there is one vote and two strong contenders then many people get no votes at all which is discouraging and also in cases like this one where getting second and third place is pretty important too then your second vote makes a lot of difference in challenges where there is one obvious leader (which its not this time).

In challenges past there has been about 50 or so people voting and between 9 entrants like this then we might see leaders getting about 8 - 10 but it drops off steep so that second and third is harder to split. When you have 50 casting 3 votes each then 150 votes gives a more even spread. In fact I reckon 9 is the worst number to have to get a good spread as its the most you can have with one vote to get the sample. Hopefully a lot of people will vote then it will be alright and give a good spread curve.