long track speed skating
I have taken photos at World Cup long track speed skating here in Calgary, as well as ice hockey. You are right that the mixed lighting makes it difficult which is why I gave up colour film. I found that I needed ISO 800 - 1600 to get decent shutter speeds at f 2.8. If you are going for creative blur and panning then lower ISO is possible. I did not find contrast a problem. The main issues were getting the composition, getting focus, and high enough ISO to get 1/250 - 1/500.
I was mainly using my 70-200 f2.8 lens, using the longer end to isolate individuals and the shorter end to include other skaters or action close to the boards. Most shots were with the longer end so you will likely use your Series 1 200mm most. It is difficult to find places to stand where shorter lenses work and the 300 is usually too long.
Without autofocus, you will need to pre focus on a spot ahead of the action and shoot when the skaters reach that spot. If you have not had much experience shooting sports, you will need to practice since the action will be faster than you anticipate. With pre focus, you need to release the shutter slightly before the skaters reach your chosen spot - remember that at 30 mph, they will travel approximately 45 ft in 1 second and it is common to have a reaction time of a couple of tenths of a second (10 ft) from the time you think about releasing the shutter to it actually happening.
As in everything, practice. Take some cheap film to a non critical event and experiment (keep notes so you remember what works) Don't be discouraged if you find you miss more than you get right - you will improve!