I've been thinking about getting myself a decent air system (still on my original tank 3000psi from when I started this year), and as a front player, is a 0.8L better (as opposed to 1.1), because of the lower profile, or does it not make much of a difference?
Without a doubt you'll want a fibre-wrapped tank, as this will cut the weight down considerably from a steel tank (assuming that is what you're currently running?).
I personally have a 0.8l fibre-wrapped tank and it is nice and light for a front player, although I don't believe there is a huge difference in weight between a 0.8l and 1.1l so you might wanna go with a 1.1l tank to get more shots per fill.