Singlespeed & Fixed Gear - Stem/Handlebar clamp size

Newb here, used search function, don't flame, etc

Anyways, right now I'm running a '79 Grand Prix with the original quill stem and chopped/flopped bars with the brake lever reversed (original lever, center pull)

http://i768.photobucket.com/albums/xx325/Bungmaster/margo12.jpg

I was wondering if there's a way I could figure out the fork size (1" vs. 1&1/8"), and the stem clamp size/handlebar width without taking calipers to it (universal size? Raleigh-specific?)

Also, I was thinking about getting a threaded -> threadless adapter with a 3T Mutant with polished track drops. Could I somehow use the original brake lever as a cross lever on the drops?

I know it's a lot of information, thanks in advance to any help.

Fork is 1" and the bar is most likely 25.4mm.

Don't use a track drops on a relaxed geometry bike, you will be having a hard time holding onto the drops and you could somehow use the lever with track drops, it just won't look as nice.

So I would definitely have to get a new stem to use new bars?
I just wanted to try different things out, what do you mean it would be hard holding on to the drops?

Depends what the clamp size is on your new bar.

You'll be have a hard time staying in the drops because your Raleigh's geometry is more slacked than those of a track bike, you'll be stretching out like Superman to stay in the drops.

Ah right, well thanks a lot. Any recommendations on a new bar? Bullhorns are comfy, but I wanted some variety, hence, the threadless stem (removable faceplate).
I was thinking about mustache bars, but a brake lever would look kinda dorky

Actually moustache bars with 2 brake hoods will give you a lot of hand positions.
http://t2.gstatic.com/images?q=tbn:qifKntoVa8nQZM:http://www.parktool.com/images_inc/calvinscorner/bars_musch_4.jpg&t=1

You should try out all the bars that you think you'll like.