Is there a rule of thumb when mounting these short nose saddles? I thought about just measuring from the stem to the rear of my current saddle but the "sweetspot" is most likely different. What's the process to get it close on the first try? I figured now is a great time to try it as I'm riding indoors the next 2 months. Any advice is appreciated.

Thanks

I'd do the same I do when installing any new saddle - lay it over the one I was using so far and try to match the widest portions and the tapers as close as possible. Measure the difference in nose length when positioned like that, apply this to the setback measurement and go into fine tuning from there.