i'll attempt
#1 it's loose so it doesn;t neccessarily have to touch anywhere
#2 even if it does since it's tofiach al menas l'hatfiach (or even a step better than that), Hashaka will transfer the water to every part it needs to
obviously this isn;t something to rely upon l'chatchila, but then the question isn;t about L'chatchila
@dan would you use a Mikva that wasn;t bor al gabei bor beshas hadechak?