hmm, tube acrylics, never used but if its the same as my tube oils, diluting the acrylics with water would be a realy realy realy good thing.
try going to a dollarama, try walmart, home depot, canadien tire( dont know what kind of stores you have around) and try to find other acrylics, mine are sold 1$ per bottle around and i get realy nice jobs using a brush. but not for ym AB, il have to get an airbrush medium so it doesnt clog up my AB nozzle ( thats using an aztek 320, now i just got a badger 150 so it might be ok) so look around ofr different types of paint is basicly what i mean... a lot of peopel use valejos( cant spell) but i never gave the ma try....
Frank