Responses to a couple of comments, but first - I have to add that just for S & G, I have been surfing some references about vintage horns. Turns out my Selmer Super is some sort of transitional between the SUpers and the aRadio Improved - has all the features of the Ser no 19xxx Radio Improved in the Vintage Sax photos on the USA site, but not the Radio Improved Bell stamp - also has a suffix letter in the seril number, which I have never heard of on Selmer saxes of that vintage. MY Conn C melody is a "New Wonder" Series 1, straight neck, finish No 4 (silverplate and standard engraving)
Now - on to responses:
Yes, I play them all. I do a lot of theater work, so usually am packing from three to five instruments to each gig. The most I ever had to have at one show was 10 for the Reed I book for The Secret Garden. (piccolo, flute, alto flute; sopranino, soprano, alto recorders; tin whistles in F, D, Bb, and Low D; panpipes; and Bb clarinet) I do not own, and did not use a sopranino recorder or panpipes; I played those parts on piccolo. I borrowed an alto flute from a friend of mine, with whom I split the gig. (The next two major purchases are going to be a decent headjoint for my flute, and an alto flute. But I have to save my pennies, 'cause each is going to set me back about $2000 US)
A couple of years ago, I decided thqt if I was serious about theater work, I needed to learn double reeds. That is why I have a basoon and an oboe. The Kohlert bassoon is pretty old (no whisper key) but I got it to teach myself the basics of how to play the thing. I got it on eBay for only $350 US, so you can imagine how terrible it is. It had no varnish left on it, so I bought a can of spar varnish from my local hardware store, and stripped the keys and brushed on two coats. It is prettyt ugly, but it seals the wood. The upper ring was missing, so I made one from a piece of scrap I had floating around in the metal bin. That was funny stuff to turn - it seemed to make a lot of dust, and smelled funny, kind of like real old aluminum. So I took a small amount in a coffee can outside and touched a lit match to it - SUPER BIG FIRE!!!! I guess I have the only bassoon in the world with a magnesium top ring. I have concluded bassoon is a lot like saxophone; it is a very easy instrument to learn to play BADLY. LOL _ I am not yet ready to play it in public; and my oboe playing is worse. I never know what is going to come out of that thing when I stick it in my mouth. I think it is posessed, hates me and stalks me sometimes while I am sleeping.
Because I do so much theater work, and becasue I have, like most of the world, a limited budget, my secondar hoirns are really second line instruments. I have them as backups for when the others are in the shop. I can repair clocks, but I don't work on my own horns; that is an entirely different art form.
As to buying a piccolo instead of a flute for a "double" instrument, I don't recommend it. There is not nearly as much call for piccolo, and it is a vastly more difficult instrument to play in tune than flute is. I was a flute major/tenor sax minor during my four year enlistment in the US Navy. I had the good fortune (some would say misfortune) to be stationed for three years in a shore-based band. That meant we were used as a "holding" unit for guys who did not have enough time left in their enlistment to serve out a full cruise. So we always had a lot of reed players around who doubled on flute. The Navy did not issue piccolos to people who were not flute majors, so I played mostly piccolo for those three years. Because I was playing an average of six to eight hours a day, five or six days a week, I got very good on piccolo, despite my best efforts.
(My only musical regret is that I did not take Arthur Feidler's offer to audition for the Utility Flute/Piccolo chair with the Boston Symphony - I have often wondered if I was really that good. But as the great ball player, Sachell Paige once said, "Don't look back; someone might be gaining on you.") But as to intonation, there is a reason for the old joke:
Q: How do you get two piccolo players to play in unison?
A: Shoot one of them.
So my advice to would-be doublers is, start with a flute. If you later want to add another instrument in the flute family, get an alto flute. Go for piccolo as a third choice, unless you are going to be playing in a concert or marching band.