By the sound of it it is low as you mention needing another coat?...Try covering the second coat with a plastic bag then seal the edges to keep the air out.
Gel cures on a mould face because there is no air, the surface you lay up on is tacky as this allows the resin to do it's chemical thang and join forces with the gel and stick like sticky stuff to blankets.......But if the gel is left too long and loses it's tackyness then there is every chance the chemical James Bond bit won't work properly.
It's not rocket science but it is a black art......
