You should be able to find a pill cutter that does not crush the entire pill. I used to cut proscar into quarters years ago and never had that problem. Also, I would not worry about the precise dosage or if it is below 1.25, as propecia itself is only 1mg. Some have very successful results with less than 1mg per day and with fewer side effects, so starting out at 0.5mg - 1mg might not be the worst decision either.
I had to cut some today so here's a pic. I try to cut them in five pieces and take them at the same time everyday. I rarely make exact cuts but that's fine as long as I get 5 mg every 5 days. The difference per day is negligible. When I am lazy I just cut them in 1/4's. It actually sounded stupid as I typed that last part since I only save a few seconds really.
You should find a pill cutter, I think it exists also for little pills. I can do it with my hands and knife only, try it . If you really can't do it, I think you can find a small pill cutter on the internet, order from somewhere, or try to check drugstores. About concentration in one quarter, I am not pretty sure, but I think that it is distributed uniformly. I searched up on the internet, and find out that bladderwrack is much better than Proscar. It's a powerful drug, so be careful, good luck!