In doing a lot of field evaluations and coil comparisons, before White's had a lot of 'V-tuned' coils, I had the 950 with my M6 to work with, as well as a 12" off the MXT-300. This let me do some larger size coil comparisons. There can be quite a bit of difference in the way certain detectors and coil or coil types perform, and I still think of a coil of about 8" in diameter as being a "standard" size for comparisons.
Unfortunately, there isn't an 8" coil available from White's at this time, but I know I would certainly like to have the opportunity to mount an 8" Double-D to work with. The 10" DD and 10X12 SEF do what they can do and have worked OK in more open areas where the trash level is lower. I had opted for the 5.3 Eclipse used on an MXT & M6 to use on the Vision the V3 I worked with and it made a world of difference in performance compared with the stock 10" D2 coil. I was mainly working some renovation sites that were quite littered with nails and other small iron junk.
When I moved out into an open field and grassy area, there was significantly less trash, but what trash there was consisted mainly of small iron. Both larger DD coils had 'challenges' on the V3. Both with audio response and visual display, and the XLT and XL Pro and M6I was using for field comparisons were sporting 950's, or an 8" Royal 800 on the XLT. On several coin targets in the 4-to-6 inch range I got good hits and very good TID's with those models using the concentric 8" n 9
