Let try this again. Assuming that between Clark and Abbot the ratio of 2nd choice votes is 20-80 (which is probably the high end of what Clark can expect), then she needs to be close enough to victory that Abbott can't catch her. The third place finisher cannot be higher than 30% and it is likely that both the third and fourth will add up to under 30%. So the highest amount of 2nd choices for Clark is going to be around 6%.
Clearly she needs to be 45% or better.