On mine, I generally keep the 6x9" Eclipse DD on it. According to Dave Johnson, who was instrumental in the design of the MXT/GMT, it was built around that coil and he has a rather low opinion of the 950 concentric. Here's some of what he had to say:":
"Back in the late 1990's and very early 20th century, the MXT was developed around the 10x6 elliptical DD. When you're used to that searchcoil, stick a 950 on and the 950 feels downright clumsy with its muddy response and bad masking characteristics. Downright insufferable. The 950 searchcoil geometry was designed for completely different platforms.
But, if you ask "does the 950 work?", well, yeah, it does. Wrong question.
I ain't gonna knock the MXT, it may be an old platform but it still works good. More than 10 years after, if you demand "ground tracking" (not that I say you should demand that), the GMT/MXT have the best in the industry. Not even Minelab (!) denies that! And as far as I know, the MXT/GMT are the only VLF-IB machines on the market with active transmitter regulation that makes it possible to work (with reduced performance) in heavy magnetite black sand, a circumstance otherwise left up to PI's. We're talking very good machines here. They may be a bit old in the tooth, but this is an industry that takes time to weed the turnips out of the beet patch. Ain't like celfonz where in 6 months the whole world has decided what kyckes and what szux. It takes time to deliver good beep verdict.
MXT. 10x6DD is the foundation. Everything else is an accessory. I am telling you this because if you are a White's loyalist, I want you to spend that extra buck, the folks in Sweet Home are my friends!"