The broadest advice I could give is that some of the biggest advantages those three ships (squid, spire, mobula) have over the rest are superior vertical mobility and can take advantage of a dimension of movement that the others can't. Buff your balloon and/or bring hydrogen and as soon as you see an engagement going badly (ie they have the jump on you, a crewman isn't in proper position, engines down) hit your reset button and shoot up into the air. As long as you have balloon health you have another chance to repair and re engage
Do your best to fly over or under to give engies most time to repair and you can do this best by juking. The squid and spires high acceleration help as you use kerosene to turn a retreat into a surprise charge as you rise over or duck under. Back to mobula you can juke by first sinking down and as soon as you see they're trying to match your altitude use your tools and stamina to rise up. They're momentum will delay their rise to keep up with you.
Flechette weapons suck but lumber jack works best at range so bob up and down to make it difficult and with carronades you should fly low. In general always fly low to start an engagement. You'll be surprised how often you'll go unnoticed but once you've identified who your attacking and from where(probably behind) then rise up in an ambush. Just keep in touch with your ally so they aren't caught out alone whilst your being sneaky
