Tonearm adjustments on the fly

VPI arms are easily adjusted....once you found what you like why bother

This last reply beat me to it. Most VPI tone arms allow VTA adjustment on the fly. And decades ago Technics produced some gorgeous tone arms with infinitely adjustable VTA that felt like adjusting a lens on a fine camera.

Most of us adjust VTA for best sound so it doesn't ultimately matter in this case what SRA is.

By the way always adjust vertical tracking force 1st. Changing VTF will also change VTA. In fact if your arm doesn't have fine vertical djustment you can use VTF adjustment for fine tuning VTA if your arm permits fine tuning VTF. First set up the hight of the arm for a VTA that sounds good after setting the VTF in the middle of the recommended range. Then very slight adjustments up and down of VTF are also fine VTA adjustments that should have no significant affect on cartridge tracking.

OP's question about what do other tonearms do?

MOST VPI unipivot arms (NOT the stock Classic 1 arm) lift the entire base on which the pivot is located.  The mechanism uses a fine-pitch screw to accessible on the arm base to make the adjustment.  Allos good on-the-fly adjustment.  

For a lot of tonearms with a "standard size" arm pillar, there is the Easy VTA base.  It replaces the original tonearm base with a hole and set screw for the arm pillar.  A fine pitch screw system using parts from a micrometer is used to gently raise or lower the arm at the arm at the pillar while the record is playing.  Once the correct VTA / SRA is attained, a set screw can be used to lock the mechanism in place.  Works GREAT on FR, Grace, Jelco and (IIRC) Linn arms.  I'm using it with a Jelco TK-850L.  Best combination I've heard.  

TransFi Terminator is a possibility. It’s a linear tracking hybrid: air bearing for horizontal, pivot for vertical.

VTA is easily adjusted on the fly. Beam horizontality is easily adjusted on the fly - and this is also a small azimuth adjustment. Large azimuth adjustments are a pain, but intuitive; ditto tangentiality, ditto VTF. All adjustments are reasonably stable and repeatable.

Low pressure air means no messy air supply maintenance.

So for a little pain and $1k you can have an instrument which competes with anything that costs less than a new car. IMO. I have two in an ESL based system, running a Koetsu and a Miyajima.

My VPI Classic 2 has that feature.

Mike