Interesting. Could you explain how you use it for that purpose? Is there a special option for that, or do you simply send a position and ask for the best move?
I have a big file of test positions which I try to solve for mate. Some are just downright impossible and are designed to find the "best" move and not necessarily a mating move (I'm holding out for a quantum computer!).
I first use the latest Dev version of Stockfish to do initial analysis with PVMulti set to 3. This helps in identifying if the best move is the only best move, only winning move, only drawing move, etc. Once I have a candidate move, I monitor Stockfish's progress. If the score doesn't go up very far after a minute, I know the position is more than likely not an easy mate candidate. If Stockfish's score quickly rises, and usually gets to a Syzygy win score, I then change the PV to 1 and let Stockfish atempt to find a true mate score. I let it search long enough to feel the score is accurate. Of course sometimes, for easy mates, it finds the score in less than a minute.
I then load up another engine for verification. I've tried just about everything including BlackDiamond, MateFinder, etc. Booot 6.3.1 seems to find mates faster than most and this is without EGTBs!
When Booot 6.4 was released, I gave it a try, but it plays a lot slower (but perhaps stronger) than 6.3.1 and in my mate tests never was faster.
The only UCI options available for Booot are the number of threads, which I set to 4 on my machine and the hash, which i set to 16284Mb.
If Booot has problems solving, I'll try another engine, but so far It seems to be the fastest for me.
If I get a score from both engines that seems correct, I note the score with the position (dm = xx) and move onto another position.
If the position is too tough, I annotate it so that I can search for it later for follow up.
That is what I do, your mileage may vary!