Firstly, I think regardless of what tape width and track count you choose, the hardest part is figuring out a good mic placement if you're recording a big band with only two microphone. What I mean is make sure you understand the importance of this and spend a lot of time testing and trying out different microphones and microphone placement to get your desired sound as poor microphone placement will be a lot more important factor in your recording than the tape machine.
Now, I believe the the recording you speak was direct to disc but I think it was a quadrophonic recording originally and so they probably used 4 microphones. Regardless, I don't think you need to worry about anything other than the 1/4" format or maybe 1/2" format. Keep in mind that 1" and 2" tape is generally only used for 8, 16 and 24 track recordings.
This is because if you are only using 1 or 2 microphones, you don't need anything more than a 2 track recorder. Keep in mind it's not all about track width here (and besides if you are looking at a 1/4" 2 track machine, you will have a much higher track width anyway than the highly praised industry standard 24 tracks on 2" tape format).
A lot of the sonic quality (dynamic range, frequency response, signal to noise ratio) is dependent on the machines electronics (as well as the mixer's electronics and what microphones you use) and this should be the focus of your attention rather than the track width. In terms of recording speed, 15IPS is the standard and most professional and semi-professional machines run at this speed.
Depending on your budget, I would probably recommend looking for either:
1. 1/4" 15ips two track machine by Studer, MCI or Ampex (generally have a more vintage character and very high quality electrical components). These are generally priced around $400 - $2000 for a working machine.
2. 1/4" 7.5ips or 15ips two track machine by Tascam (32, 42, 22-2 etc) or Fostex (E2) IF portability is an issue. Price range is about $100 to $800 for a working machine.
3. 1/2" 15ips or 30ips two track. ONLY if you are very patient (as working 1/2" two track machines are VERY rare) and are willing to pay up to 4x as much for tape (costs almost twice as much for 1/2" tape than it does for 1/4" and you are recording at double speed so you get half as much recording time per tape).
I would go for option 1 if it fits in your budget and the machine doesn't need to be moved around too much. Option 2 is my recommendation if you need the portability or have a tight budget and I don't recommend option 3 at all unless you have very good sounding microphones, have the time and skill to position the mics in the 'sweet spot' and are running them through very good preamps because otherwise the investment and headaches with these machines isn't really worth it.
Another thing is, don't buy machines that are untested or very worn out unless you are willing to (and capable of) repairing it yourself or fork out the money to have it repaired and maintained by a technician.
