ive used zip ties, screw clamps, spring clamps, and the plastic ratchet clamps.... they all work fine...
but i would sayd screw clamps would be the best.. but COULD leak...
spring clamps work best, but do cut soft tubing, and youll need a pliers to put them on and off.
plastic ratchet clamps suck trying to get off.
zipties suck to get off too.
my favorite overall method to securing tubing is simply using barbs that are one size up.
so go get some 3/8" silicone and use 1/2" barbs... even even run 3/8" on 3/8" (silicon and vinyl) and havent had a leak yet...
well i DID have a leak... but thats cause i use a barb that was cut in half... DUH