Keep in mind your galleon's silhouette as well. In a medium-to-long ranged shootout, you can use your balloon or hull (based on what kind of shells are coming in) to bodyblock damage and give your ally a breather so they can repair up and get back into the fight. In my experience the galleon plays best as the shield in a shield and sword combo despite your heavy weapons. You dictate the terms of engagement by picking your position and fire lanes, but you are best served by an ally who can physically knock an enemy out of his or her threat arcs and into yours. All this talk about a rear-mounted minelayer is nice, but it won't prevent an enemy from settling on your 12 o clock high and grinding you out. Thus, I prefer to play the galleon if I have at least one goldfish or pyramidion in my fleet who can sit either off to the side under cover or behind my hull, ready to go aggressive at a moment's notice and ram close-ranged bogeys away.
Of course, this requires several things. Primarily, it will require your allies to grant you command authority and respect your shot calls. Secondly, it'll require you to make those shot calls; so brush up on your situational awareness, captain! Last but not least, it will also require your allies to be able to respond to your calls. I generally only fly galleon either in large games where the law of averages will usually provide at least one tractable ally (determined during pre-game lobby) or with captains I know already or clan mates. Your best bet is to dive in, fly it, learn it, and build up your connections with other captains. Few feelings in this game are better than winning an engagement from a de facto fleet command position and being the driving force behind that teamwork, and I hope you can enjoy that feeling soon. Cheers, and see you in the skies!