I was given this a year ago. A quick clean of the switches and the four speed pots (two on the mother board and two on the plinth, coupled with some fine oil on the main bearing and we're ready to roll..
The Grace 707 was donated to me decades ago when a good mate upgraded to an Ittok on his LP12. The low capacitance cable needed new phono plugs and I carefully fitted some basic Neutriks, taking great care with the inner conductors, which are hair fine.. The cartridge is another Supex 900E Super I found, cleaned and has a fine beautiful tip on it.
Interesting sound this one. The mid is cleaner than the Dual, which I expected it to be, but the plinth is a bit "lively" and any light tapping comes through. This is where mats come in...
I still have some fine tuning to do, but I quickly found the "tapping test" sounded very different depending upon the mat used. I've only tried three so far, but the Herbies/Sound hiFi one was the worst for this one issue (but good in a musical sense), the techie original mat (which is quite heavy) was better and on this sample of SL-150, the Spacemat was the best of all and kept 99% of what the Herbies mat was doing, which it didn't do so well with the Dual 701.
By the way, the grace arm is bolted to the rear of the SME cutout, using both the solid and rubber "washers/mounting discs". The arm plate rests on a thin rubber gasket and is held in place with knurled headed finger screws with thin nylon washers under the heads.
I'll report later if anyone's interested....