Piedpiper : I found that filling the tube with mortight affected tonearm/cartridge compatibility.
To me the compliance factor changed perhaps because the total effective mass had been altered. For instance, Grados did an accelerated "Grado dance" and my Aq 7000fe sounded strident ,as did my dynavector and a slew of other pickups. By changing from mortight to compressed natural fibers ( in my opinion ) gave me more options -- damping varients which returned my TT to audio-heaven . Generally, most published material on the subject suggests tonearm/cartridge resonance issues revolve around the front of the tonearm. However, when you are dealing with with an "L'-ish" styled linear tracker supported by air bearings & effectly floating on air, weight/damping issues from either the front or back maybe a problem. I took note of the fact that it appears L.Walker maybe attempting to eliminate the above by his use of a air bearing tonearm design that is in open architecture , that can be viewed/copied from web pages on the internet for diyers. Good for LLoyd.
Am I crazy ? Yes sir I plead guilty as charged. But so is Pierre , LLoyd and lots of others. As you are a friend of Pierre do you reside nearby ? Should you know the name Ejazz than you know the audio-heads that make up the crowd. Some of those Kats don't think nothing of dropping 15 to 20K in a blink and trashing the rigg if they find a "better one" . Me I'm different . I try to squeese every ounce of sound out of what I own . To that purpose I reserve a few hours everyday to read Audio stuff and having done so for 28+ years. That doesn't make me smart just ahead of the curve.
Frankly, as far as I am concerned you can spend a Kilo bucks and not get one ounce more than a tricked out 'Noll. Crazy...Yep like a fox. Oh, if your really nuts try a Shun Mook record weight. Worth every $$$$. Cheers