Jim is a good guy, I actually found his mandolins when visiting the mandolin store (brenton.us/mando then the neck wood is probably what you would be looking at. Granted necks are thin so its hard to get a more flat-back image in your mind but you can kind of gather the color and pattern of the wood from the neck. I saw the block of wood and it was a decent chunk, so he should have plenty of that. When I was in his shop I saw some of his Curly Maple mandolins that he was finishing up, and they were a very nice piece of wood too, very curly and wavy, I am tempted to get one of those too. I do say that my mandolin has a very good sustain. It rings like a bell. It is quite loud too, I really like it a lot. I don't know if there is much of a difference between the Mahogany and Maple sound, I guess perhaps the Mahogany might be more bright? I don't have a way of judging really, but I do like the Mohagany on mine and it has a nice sound. It's quite a loud little guy. I went with the blood wood binding and veneer, and it was my preference to have double diamond on the 3rd fret, so just so you know, if that is not your taste, it was not his doing it was mine, but the Diamond Inlays are a very nice piece of Abalone, it glows in person, I like them a lot. I don't think you can go wrong with the Mohagany or the Maple, both look really nice.
I have never been big on dot inlays myself, (granted I just bought a mandolin which has dot inlays), but my preference, i like to add a little ZAZ to an isntrument than the old fashion Dots. So that is a preference as well.