Wolf,
Ooh, that 'driven by a woman' comment is bound to come back and bite you in the butt . . .
Tom, as for the jack . . . my 75 has the original jack and handle. They are in the rear storage area on the left side of the car, right behind the passenger seat. I do not believe that a bottle jack will fit under the car at the approved jacking points. Even my hydraulic floor jack can be a little bit of a problem, as I found out last Friday when I took a self tapping screw in the right rear tire. Reproductions of the original jacks are available from a variety of vendors . . . places like Corvette Central, Jegs, Doctor Rebuild, etc. They are not terribly expensive and I have heard that the quality is generally quite good.
Concerning tire size, I had a similar question that I posted earlier today. Chris (69myway) came back with some very good information concerning sizing. He has actual experience with tire sizes on C3s, which he was kind enough to share. Take a look at my thread on tire sizes posted this afternoon (Monday).
I have absolutely no idea where to begin looking for a space saver spare for a C3. However, wheels that will fit are pretty much a dime a dozen and most any tire store will sell you a used tire with acceptable tread left on it for a spare. Usually, you can pick one up for ten bucks or so. Used to run used tires on the front of my dune buggy, since in that application they get pretty torn up . . . so it didn't cost me a fortune keeping new (er) shoes on it. Plus, who wants to spend 100 bucks on a spare tire for your Vette unless it is going to be judged.
I hope some of this information helps.
BTW, I mentioned that I had a flat on my 75 last Friday. I need to express appreciation and put in a plug for the folks that fixed it. Out here in Southern California, we have a tire chain named Discount Tire. I have dealt with them in the past on one occasion. Anyhow, they have a store right around the corner from my home. I took the Vette tire down to get it fixed. They accomplished the task in less than ten minutes and when I went to pay, they refused to accept money!! Their policy is to fix tires, regardless of who you bought them from . . . only asking that you consider them when it's time to replace your tires. I swear, you just don't get that kind of service anymore, at least not from very many places. This phenomenon may be isolated to this particular location, but as a man who's wallet squeaks when he walks, the gesture was greatly appreciated.
Just my two cents . . .
Ron