Most of what I will share with you stems from my personal experience with the instruments you are asking about. Some of it is derived from what I have read and heard (videos) on line, as well as from conversations with others. Martin Style 3s and 5s were made by the more experienced luthiers in the Martin shop. The grade of wood selected for use, particularly on these more expensive koa models, is higher...at least it is prettier. You can clearly see this in comparing pictures of 1ks vs. 3ks or 5ks. In my experience, sometimes the earliest Os, 1s, and 2s are louder than the 3s and 5s, but the 3s (I have not played a vintage 5) seem fuller, richer and more even in tone. To my ears, at least potentially, the lower models can have more bark. You may be able to hear the difference by listening to some Winin' Boy videos where he plays the lower styles vs. a lovely 5K he has. Or, compare the sound of Winin' Boy's ukes to Ukulelezazas. Then there are just differences in tone between individual ukuleles. My friend has a 40s-50s Style O that sounds punchier than my 1960's version, one that I would describe as more harp-like. I'm still lusting after a certain style 2 that I played a year ago that sounded like a cannon going off. You can really drive yourself nuts with all of this though. There are so many factors beyond the construction of the ukes themselves that make adjustments to your such judgments difficult: strings, the acoustics in the room; and I really believe it's difficult to hear what the ukulele sounds like when you are playing it. In the best of all possible worlds you are presented with an array of different ukuleles, you can compare them side-by-side to make decisions about the playability, and you have a friend along who can play the ukes for you so you can hear what they sound like to a listener. Of course, this is less than likely. All of that said, vintage Martins sound quite similar one to another, as compared to say a vintage Martin vs. a vintage Gibson. On the brightest side, I've never played a vintage Martin that was not really good in terms of playability and tone. In other words, you're not going to go wrong, but you may have little control over whether you go really right, if that makes sense.
The 20s and 30s Hawaiian ukuleles I have and have played are interesting (I must say that your UAS and mine are the same
. They are very loud, very strident (my wife would say too loud and too strident). Some of this, I think, has to do with the fact that, at least the ones I can write about, have no bridge plate. It's an interesting tone, but I would not say it's a great tone, especially as compared to Martins or even newer Hawaiian made ukuleles. I do love the way the old Hawaiians looks, though. Playability, however, is another matter. In my experience, they don't play very well. The action will go from low to very high over 6-1/2" of neck (no fretboard, straight neck). They are fine, therefore, if you play (or especially strum) until around the 5th fret. After that, it gets a little challenging.
