hehe pretty nice,
I got 1.10 mm for the slides, graph gradient = -0.0440 and intercept = 5.10, A was actually my V0 ie. 160 mV and B was 0.0440
The 50% thing was (ln 2/B) * (measurement of slide) - worked out around 17 for me. For the second question I said that T is proportional to root m, my two values of K were within 3% of one another.