Gimbal vs unipivot tonearms

no worries with a warped VPI....they send a new one.

I am unsure if any of these tonearms would suit your particular turntable. However, based in the UK, I am using an Audio Origami PU7 on my Linn LP12. It tracks beautifully and sounds superb
Other mainstream arms in the UK that might be worth a look also are the Roksan Nima or Roksan Sara.
All depends upon budget and suitability of course.

Sorry to everyone for my error about the SME arm.

It's in a box downstairs, I thought I had sold it, now I remember that knife edge, thanks for correcting me. 

What I wanted to say, is

there is a difference between seeing the parts, knowing gravity has been equalized (as you do with the SME)

and trusting that it has been i.e. quality of my Gimbal's machining/parts, and the resulting 'equalization' of forces/freedom of movement.

and trusting unseen parts, like my Acos Lustre GST 801's internal magnets.

The methods of retaining settings, again like the SME, can give great confidence, or, like my Acos, requires 'belief' after setup.

I rarely checked my SME after setup; I often check my Acos's unseen magnets. 

@lewm , It is due to be in production mid July. They have their entire crew back now so it should speed up. I have the arm and all the cartridge mounting plates (various weights). The Smartractor is on standby. 

@rodman99999 , Son of a Gun, another Tact user. I used an LP 1 for 4 years on RH Labs subwoofers, a landmark product. The Tact is so superior in regards to bass management you can't compare them, not fair. What makes you believe the Tact does not go below 20 Hz? My 2.2X goes down to but not including Zero. Get one of these https://www.parts-express.com/Dayton-Audio-OmniMic-V2-Acoustic-Measurement-System-390-792 You will be amazed. You can then create individual target curves for each channel so they match perfectly. The Tact does not allow you to see the system's frequency response after correction. You will not believe how your image will snap into place.
I have used every type of tonearm known to man except the Schroder LT which I am dying to try. The best tonearm you can buy at this time other than the LT is an intermediate mass, two axis, 9 inch arm. The advantages outweigh the greater tracking error. My experience and test results measuring distortion by oscilloscope bear this out.  Theoretically a lighter arm with a high compliance cartridge should have lower distortion but the problem becomes making the arm stiff enough to dampen all resonance in the audio band. None of the ultra light arms have been stiff enough not to mention that it seems the day of very highly compliant cartridges is over. vinylzone is a typical example.
@daveyf , air bearing arms are not worth talking about especially with the Schroder LT available. They are a defective design right from the start. The only way to make a straight line tracker is with an animated carriage like the original Goldmund turntable. But that is a crazy expensive and complicated thing to do and maintain. None of these tables survived. I think the B+O was the most successful but, it sold to a different audience. Audiophiles have to be able to tinker. This is one of the reasons turntables survive. Digital is no fun! Tinkering with the B+O was impossible.