I pinged one of our tárogató experts, hoping to find him available. I know a lot of people buying a Bb tárogató (like I did) tried various soprano sax mouthpieces with some success. In my case, if it played relatively in tune across the range of the instrument and with a pleasant sound, I was happy. Trying to remember if I ended up with a sopranino or soprano mouthpiece. Fortunately my instrument came with an original mouthpiece. I felt the sound was too oboe like for my liking plus the learning the fingerings with any fluency put me off and I ended up selling the instrument. Cheers.
Hi Tim, Ioan Scaunas makes very good tárogató mpcs. He is an amazing player (see YouTube) and has the world's largest collection of Stowasser tarogatok. I believe his e-mail is
jstarogato@aol.com. His English is limited but he does communicate.
His mpcs are around $300. I have one. It would be my mpc of choice for loud playing--it has edge and much more projection that the Stowasser and Gruber mpcs I have.
Speaking of edge--he has three flavors. Unless you want the Romanian buzzsaw sound, I would go with the least bright. He will pretty much make it to taste for you. Here is a page from 11th Muse.
http://www.11thmuse.com/Scaunas.html
I have had no luck adapting soprano sax mouthpieces. The tárogató requires the lower part of the chamber and upper part of the throat to be constricted to about 9-10mm. In the absence of that the instrument will play extremely flat and the intonation will be generally terrible. I have about six or seven mpcs and various tarogatok and I have done a lot of experimenting with mpc volumes. That is critical--not least because the actual range of movement for tuning is limited, and also because when you do move the mpc, the volume increase (that accounts a lot for tuning in conical woodwinds) happens behind the constriction in the throat, not in front of it as in the sax. I daresay that many of the intonational difficulties attributed to the instruments themselves (and there are plenty of those) are on account of mpc problems and not because of the tárogató body.
For instance, I recently bought a Hammerschmidt tárogató. When I tried it out of the box with the included mpc, it was playing horribly: about a quarter tone flat near the bottom and more than a semitone flat in the short-tube notes. Putting a Stowasser mpc on corrected that immediately, but I also found some intonational differences between Stowasser mpcs that all played pretty well on my Stowasser. Another factor to be considered is playing style: many of the instruments themselves seem to get sharp as you head up the first octave near the top. This seems to be because they are designed to play with a very loose embouchure, which tends to flatten the top-tube notes more than the bottom-tube notes. I have done extensive work with crescents (actually usually wood putty)--and sometimes a good needle file--to tune the actual finger holes to either reduce or enlarge them. But the first thing is to get a decent mpc that plays relatively in tune and then adjust for individual note variations.
Ioan is very knowledgeable and will help you get the best out of your instrument. He does, however, play in Romanian style. If you want a more rounded sound be sure to let him know. It is very much like the difference between classical and very-high-baffle sax mpcs.
One final caution: there does not seem to be anything like a standard in body tenon sizes. Make sure he knows the exact inner diameter of your present mpc tenon receiver.
Good luck!