I formerly used a hefty 20 oz. tank run vertical on my own Sniper 2. The marker performed admirably, despite being an unwieldy beast. I suspect a 12 oz. tank would work much better. If you find the set-up unsatisfactory, bottomlines can be had for relatively cheap.
Trouble is like urine in a swimming pool - the only way to make sure you're not in someone elses' is to make a little of your own.
Don't piss down my back and tell me it's raining.
Digital pants - activate!