How much work time before vinyl-ester starts to kick?

Depends on temp, humidity and catalyst ratio. Can be 10 minutes to several hours

+1. Different batches have different kick times too and quantity will effect it also. If you mix up say 30 oz in a quart cup it will go off quicker than 30 oz in a 2.5 qt cup or if you pour it in a paint tray. Large quantity in a smaller container will go off quick.

Too many factors to give a specific time.

What does higher humidity do? Cure faster or slower?

when all weight out properly with the mek i averive between 30 to 45 min before it starts to gel up..

yep, a good quality VE at aproz 70 degrees will give 30-40 min. I would think higher humidity would speed it up a bit though.