Also, note the 3300 is a 1/4 track deck unless it is a 3300-2T.
To amplify that, tapes recorded on it can be turned over like a cassette and recorded on the other side. That's okay for consumer stuff, but for a mastering deck you really want a 1/2-track deck, where the two channels are spread across the entire tape. That gets you an improvement in sound quality, but the tape will play backwards if you try to turn it over.
For mixers, it depends how you work. What many people seem to do is get a mixer with more channels than the deck - e.g. 16 channels for an 8-track tape machine. Then they use half the channels for mixing, and the other half are fed into the tape deck to act as pre-amps and EQ for the incoming signal.
What I do myself is I have two mixers - a sub-mixer at the front, that feeds into the tape deck (for pre-amps and EQ etc), and an actual mixing desk which I use to mix the songs. That helps me in that I can get away with a 16-channel mixing desk if using 16-track tape, etc.
It probably helps that I always record things layer by layer, though - if I was recording an ensemble I would have to do things differently.
I can do a block diagram if it helps :3
For 16-track machines, the Fostex E16 and G16 were quite popular in the day - they record on 1/2" tape and use Dolby noise reduction. There is basically no parts support for them nowadays, though.
TASCAM's entry in that market was the MSR-16, which again records on 1/2" tape.
Moving further up, there are 1" 16-track machines like
the TASCAM MS-16 and ATR60-16. There's also the 8516, but that's going to be pretty ancient by now and I gather the original model (non-B) had a problem with the capstan servo causing it to make weird fluttery noises at 3KHz on certain types of material.
Bear in mind that 1" tape isn't cheap, I've just spent £90 on one, shipping and tax included. They use DBX noise reduction.
Otari also had a 1" 16-track machine, the MX70 I believe, but it will be pretty hefty and probably rather expensive. I don't believe it had noise reduction built in.
After that, you've got 1" 24-track machines like the MSR-24 and Fostex G24. These are liable to be expensive if something goes wrong, and you'll spend a lot on the mixer. The Fostex uses Dolby S, I believe. The MSR-24 is DBX, and the MSR-24S used Dolby S, but there was a problem with this and for the most part, the noise reduction cards have died (avoid!).
After that, basically you're left with the 2" machines which will be very expensive to run, but are basically IT - as high-end as you can go with tape.