The T-2 is one of Heath's neatest Signal tracers because of that universal output transformer. The front panel markings for the two switches tell most of the story in using the output transformer. All of the impedance markings are based on feeding the internal speaker which I assume is about 4 ohms. The B+ connector is the center tap on the transformer. The switches can be set for either single ended audio (B+ and P as the connections to the radio under test) or double ended push-pull (connections to P, B+ and P). For example, a single ended 6V6 typically sees a transformer of about 5K or 6K ohms impedance. The nearest settings would be 6000 with switch 1 set at position 1 and switch 2 at position 3. A pair of 6V6 tubes in push pull see a typical output transformer at about 8K or 10K ohms. The nearest setting would be S1 at position 2 and S2 at position 5 which is 9600 ohms. Make sure the power switch is off when using the output transformer settings.
Note that the P,B+, P impedance switch settings are exactly 4 times each of the B+,P settings. That's because impedances are the square of the turns ratio of the transformer. A full push-pull winding (P, B+, P) is twice the number of turns as compared to the center tap to either P (B+, P). Squaring twice the number of turns gives four times the impedance.
The signal tracer is just a little high gain audio amp. The probes are not critical. A simple pill-bottle KIS probe as described at this link will work fine. A probe from a T-3 or T-12 or anything incorporating a capacitor and a germanium diode will also work. An audio probe can simply be a small capacitor at the probe end. (or use a switch to short out the germanium diode). The cap keeps DC from the radio under test out of the probe wire and tracer.http://www.ohio.edu/people/postr/bapix/SigTrac2.htm
Best wishes with that T-2.