If I were you and I wanted to use HC-110 at 1:100 (which I will do soon), I would expose the film normally and use about 50% more developing time. Maybe more. It usually takes a couple of rolls to calibrate something like this.
What I do is I expose one roll and I bracket. Say it's Plus-X, I would expose at EI 100, 50, 25, and 12 (just for the fun of it), in normal contrast scenes. Then I develop for a certain amount of time, say normal 1+50 time plus 50%. Then I look at the negs, maybe scan them, and see which has best shadow detail.
Then I shoot an entire roll at that exposure index, and in the dark I cut it into three pieces. Then I adjust development time until my highlight density is where I want it. Voila. That's it. Two rolls. The reason I answer like this is that there are so many variables between your, mine, and everybody else way of photographing. Camera shutter, light meter, how you meter, lighting conditions, even water quality matters.
Good luck,
- Thomas