yes spray is the best, rollers second best. lots of coats like they say and let it dry a long time. usually twice as long as it says on the back of latex paint. it isn't soaking into drywall, it's on hard glass. the glossier you go the more expensive, but also the less flaking you will have. higloss also won't look any different through a foot of water and glass. also don't believe the people at home depot or lowes or whatnot, they don't know. go to a reputable store that sells only paint, get advice, and then go to hd and buy the cheaper behr. i don't really recommend lowes or hd america paint. cheap stuff w/lots of water and little TiO2. i'd also stay away from all oil-based sprays (most rustoleum) on tanks although it is the best for metal stands. e-mail any questions maeistero - gmail
p.s. acrylic, water-based, latex, these are synonyms now in the paint industry.
paint store manager guy and tank painting veteran now.