97grnrs

i just got a blow down tube for my dry zex kit. i know it screws on where the little cap is on the bottle but can i unscrew the safety blow off cap when the bottle is full or do i have to wait till its empty? and also my bottle stands straight up and down so the tube ends up pointing to the side of the car. can i cut it shorter and attach some heater hose to it and route it outside or no? i called zex but they didnt help at all.