Sometimes you have to work three sides of a four-sided square. Go to Flickr, as I've just done, and search "beutler orwo" and you'll get a number of photos -- like this one:
www.flickr.com/photos/aprilman/7874683834/
This photographer kindly lists his temps and times for Orwo UN54.
Then go to Massive Dev Chart and choose a developer, maybe D-76 as a standard place to start. See what the development times are for NP15 and UN54 -- does one need more time than the other, and if so, how much more or less? Do this with another developer, perhaps D-23, and again see if one needs more or less time than the other. You should start to see a pattern emerge, that NP15 needs either more, less or the same time as UN54.
With that knowledge, you can take the temps/time/agitation from flickr photo and adjust your time up or down accordingly.
It may not be perfect, but I think it's a reasonable approach to getting a ballpark starting point. You can do the same for the other emulsions you are interested in.