use a screwdriver to force bits of rubber in,
you can use Hosepipe, old rubber car mats work,
wet your fingers when working with sikaflex or any other silicone,
Ok, will definitely wear gloves, if it's anything like expanding foam (like I imagine it to be) then I can see it being hella sticky!
Just got hold of some sickaflex, will hopefully be giving this a go tomorrow, hope it helps
Thanks