I'm going to repeat what I said in the past: if you can just get the monster manual for this and just make up the rest of it. I can pretty much guarantee you will put more thought and effort into it then WotC did since:
1. The module is a checklist of bad design decisions.
2. The player race options are interesting but not particularly compelling... unless you want to bully your GM into allowing guns into your campaign.
3. There is a near total lack of rules relating to owning and operating a magical boat that flies through space and what does exist is kind of insane for somethings (Spelljammers accelerating from a speed of 40 to "a million miles per day if there are no objects within 1 mile" and how wildspace/the astral plane creates all kinds of weird rules incoherence (this isn't even getting into how the prime material plane isn't contiguous and exists as a series of islands in the astral plane apparently).
4. There is no actual suggestions or sources of information for who exactly in this setting beyond incredibly broad strokes monster entries that do almost nothing to establish their histories or relationships outside of Githyanki and Illithid.
Honestly it's the first time I bought a D&D product in the past 20 years and was legitimately angry after the fact.
Firearms during the 1860's produced a lot of relatively thick, acidic smoke that turned many battlefields into oxygen drained, acidic fog banks that hampered vision. Shooting off firearms in the enclosed space of a spell jamming ship ought to suffocate every living being on board such a vessel. Modern day firearm propellant powder does not produce as much acrid, foggy residue BUT do your players know how to make firearm propellant powder? If your world does not know how to make saltpeter or any other components of firearm propellant powder, then guns will probably be impossible on your world.
The thing I was reffering to was how Giff (a playable race) have firearms as an almost Texan level core component of their cultural identity; They Litterally have Firearms Mastery as one of their 3 traits (the others being hippo build which effectively lets them count as a size class larger for strength checks) and Astral Spark which lets you do extra radiant damage on weapon hits.
Remember the old DM admonition: if an NPC, such as a Giff, has a flashy weapon or device, then one (or more) of your player characters will somehow grab that weapon or device and claim to know how to use it.
If you do not want firearms floating around in your campaign, then do not let the Giffs, with their affection for loud, flashy firearms, into your campaign. Or, at least redesign the Giff firearm as an uncommon, low power Blast Scepter that recharges each day.
I am not being mean, I am just being careful about setting off an arms race in someone's campaign world.
On the other hand, you could adapt the Artificer in the Eberron setting for the Giff in the Spelljammer setting, in that the Giff firearm is simply a version of Artificer's Artillerist subclass. You will still have player characters with a touch of envy concerning that firearm but that is another matter.
Alternatively, do you want your Spell jamming ship to be outfitted like a steam punk space vessel or like a World War Two era B-17 Flying Fortress bomber that had .50 caliber machine guns literally pointing out of every nook and cranny? (I am not kidding, look up the specifications for a B-17 Model G bomber.)
Late addition: my late father was a fighter pilot in the U.S. Army Air Force during World War Two; he made sure that I knew the planes of the Army Air Force.
The thing I was reffering to was how Giff (a playable race) have firearms as an almost Texan level core component of their cultural identity; They Litterally have Firearms Mastery as one of their 3 traits (the others being hippo build which effectively lets them count as a size class larger for strength checks) and Astral Spark which lets you do extra radiant damage on weapon hits.
Taking Guns away from them would be... mean.
Remember the old DM admonition: if an NPC, such as a Giff, has a flashy weapon or device, then one (or more) of your player characters will somehow grab that weapon or device and claim to know how to use it.
If you do not want firearms floating around in your campaign, then do not let the Giffs, with their affection for loud, flashy firearms, into your campaign. Or, at least redesign the Giff firearm as an uncommon, low power Blast Scepter that recharges each day.
I am not being mean, I am just being careful about setting off an arms race in someone's campaign world.
On the other hand, you could adapt the Artificer in the Eberron setting for the Giff in the Spelljammer setting, in that the Giff firearm is simply a version of Artificer's Artillerist subclass. You will still have player characters with a touch of envy concerning that firearm but that is another matter.
Alternatively, do you want your Spell jamming ship to be outfitted like a steam punk space vessel or like a World War Two era B-17 Flying Fortress bomber that had .50 caliber machine guns literally pointing out of every nook and cranny? (I am not kidding, look up the specifications for a B-17 Model G bomber.)
Late addition: my late father was a fighter pilot in the U.S. Army Air Force during World War Two; he made sure that I knew the planes of the Army Air Force.