I have owned the Spacedeck and Space Arm for about 6 years now and am pretty happy with it, aside from the cueing mechanism needing to be replaced as I type this and wait for the new unit to arrive. I have a very slight 60hz hum at VERY high volume levels. I can move the connectors from the TT to the phonostage around a bit and get louder or softer hum, so I have compensated by arranging those in a configuration that results in the lowest hum possible. When I switch the input to a digital one, the hum instantly vanishes so I am reasonably sure the issue resides somewhere between my cartridge and the outputs on my phonostage.
Oh man, you nailed it perfectly bcowen, the two things that irritate me most about this system are those you mentioned.....azimuth adjustment (or lack thereof) and the collet around the armpost!!! While I AM able, unlike you, to twist the headshell on the end of the arm (a very suspect process as it imparts a lot of torque to the graphite arm which is very concerning), it is HIGHLY unlikely that you will get an accurate result unless you are just plain lucky. Having a friend with a Fozgometer, we worked for quite a while before getting a setting that the meter showed to be proper, and then it was close, not perfect but I'll live with that. The second thing, tightening the collet around the armpost, just makes no sense to me at all because, if you hold the tonearm with your left hand while tightening the collet, you can FEEL the arm moving out of the original position as you tighten the grub screws! So, reflecting on what Mr. Fletcher has said on many occasions, "the meaning of tight," I have found that by just a VERY light snugging of first one, then the other, then back again to the first, repeating this at least 3-4 times whilst holding the tonearm in the other hand has resulted in not much, if any motion imparted by the tightening to the position of the arm. That's how I do it anyway, and I only tighten it enough to keep it from moving when I use the cueing mechanism. This you will need to experiment with but with GREAT CAUTION as one that is too loose can result in the tonearm moving across your record as you try to lift it up with the cueing mechanism and that has obvious undesirable consequences.
Hope that helps you out some in your contemplations.
Meanwhile, my effort at restoring the old lift mechanism (see my earlier post this week) resulted in failure. Couldn't find the proper lube here locally and was just about to order some of the Kyosho 500,000 cSt stuff online when under close inspection, found that the end of the piston where it engages with the cam was worn to some extent so decided to pop for a new one from the US distributor in Florida, Hollywood Sound, who by the way are very good to work with and offer a very personalized level of service, taking time to talk with me about the issue I was having and providing some excellent guidance without which I would still be trying to figure out how to get the old one off! No affiliation, rest assured, just a happy customer who does not hesitate to pass on good recommendations to my friends where they are warranted. Talked with "Marc," by the way, and he's a gentleman......