Bill
If you are concerned about lengths of available lines you can always buy a coil, I believe it comes in 25' length from NAPA. I think McMaster also sells it.
The only problem is you need to buy a bunch of inverted flare nuts for your connections, and the line is tough to get really straightened.
I would run 1/4" lines for the clutch and rear brakes, and it is generally ok to run 3/16 in the front.
The problem with running a small diameter line for the clutch is sometimes the fluid takes its time returning, and the clutch will engage slowly after you have released the pedal. This happens more in winter weather, but running a 1/4 line will insure it is ok all the time.
If you really don't want to use double flared lines you can also opt for stainless lines with a single flare. The fittings are a little pricey, and they use a little backup spacer to hold the flared line in conjunction with the nut, but they last forever, rarely leak, and are good for about 5000 psi which your system should never see anyway. I believe they are called JIC fittings and McMaster also sells these. The lines are a bit tougher to bend, but look great, and there are various fittings available such as line to pipe thread, tees, elbows, mostly everything you might need.
I would take Brian's advice on the master cyl. sizes, as every system is different, and matching the cyl. size to your calipers piston size and number of pistons is important. Also a larger rotor diameter, size of the pucks etc. affect the overall performance.
A smaller master cyl. may give you too much pedal travel that you may not be comfortable with, a larger cyl. will give you a harder pedal, but may not stop the car well.
Last but not least do the math on your pedal ratio, most run 6 to 1 or thereabouts.
Where the pedal is 12" long from pad to mounting pivot, and the master cyl. connection is 2" up from the pivot is a 6 to 1 ratio. An input of say 100 lbs of foot pressure will give 600 lbs. of force to the master cyl., Take the radius of your master..lets say a 3/4" master cyl. is being used so the formula would be .375 X .375 X 3.14 = surface area ( .4415 sq. in.). Divide that into the 600 and you get your line pressure of 1359 psi. A bit high but maybe necessary with small pistons in the calipers. Going to a 7/8 master will drop your pressure to under 1000 psi so small changes can make a big difference here.
Hope some of this helps
Cheers
Phil