I have not yet had an opportunity to play a Mauriat but I have owned a YAS-61 since new (1975) and it is a magnificent sax. Here's something I'd suggest you think about, if you have not already. I use my Yamaha for playing earlier David Sanborn type jazz and balls to the walls rock and roll, Average White Band (pick up the peices) type stuff. It's also a great horn to cut through heavy ensembles such as big band orchestras while playing lead or doing solo work. My set up for the yamaha is generally a Dukoff D7, Brilhart level air number 6 and sometimes a Guardala, although it's a bit too closed for me on some situations. However...if a more complex tone colour and a broader depth of my overall sound is what I'm shooting for then my Mark VI or Ref 54 is what I play. I scale down the mouthpiece a bit on this set up by using a Hard Rubber Supper Sessions D or E facing and sometimes I'll use a New York Myer number 6. These work best for me to do what I want to do in smaller rooms and close quarters. (Pubs, studio, etc.) If I am to be outdoors where I can really blow without feeling I am being too obnoxious...it is not so much an issue which horn I play. I would suggest keeping your 61 to use for rock, big band jazz and the like and to go with a horn that has a reputation for producing a darker sound, such as an H Couf, SML, Keilworth, Selmer, etc. for the studio and small night club stuff. Owning both types of horns will give you more tools in the shed. The Mauriat may be just what you need to round out your axes. I find it's always a good idea to have a spare horn, just in case something goes wrong.
But you know what? If you try a new horn and you immediately feel you have been bitten by the love bug and you just have to have it...you should get that sucker!! A horn is a very personal thing. My favorite horn on the planet, and I am an old guy and I have played virtually hundreds of horns, is my Reference 54 alto. But... that's me! Other players might think my horn is terrible! What matters is how I feel when I play it and what my body can do to produce through that hunk of metal we call a saxophone. All I know is that my horn works best for me and I can do things playing my 54 that I cannot do when playing my Mark VI or my YAS-61. The Mauriat you are considering just might be the horn you were destined to play, just as I feel my 54 was made just for me.
It's a bit like falling in love....
When you know...
You just know!
Best of luck to you.
Bill