Tone arm holes do not line up - best way to attach TT?

After all this, ensure your diamond is still on the cantilever! That could explain the gliding across the grooves.

To sum up, the following questions are up for grabs:(1) The definition of "P2P", a term mentioned by the OP in passing.  Which would possibly reveal that mcmanus is measuring pivot to stylus tip, not P2S.
(2) The actual effective length of the tonearm.(3) The (remote) possibility that the wiring is dragging on the arm wand, or I'll add another, that the pivot bearings are too tight, preventing free movement of the arm wand (although that would probably not result in the cartridge skating all the way across the LP surface).(4) Diamond tip has fallen off the cantilever; it happens.

“All the alignment we’re doing is to get the record to drag the stylus across smoothly without too much error. That’s why someone came up with the idea of your long arm in the first place. A longer arm means a longer radius means less angle change across the record. This is all based on some guys idea. Its important not to get too caught up in some guys ideas”. MC

The 12” arm or 282mm effective length tone arm was developed by Micro Seiki and still, after more than 40 years, is very effective and one of the best. My TT is a MS BL-91L and the arm is an MS-505LS. Specifications follow:Effective Length 282 mm
Overhang 12 mm
Offset Angle 21.833°
Pivot to Spindle 270 mmNull Points 38.7 / 171.0 mm

I use an Allaerts MC-1 boron or Ortofon Cadenza Bronze cartridge.

Summary is that the long arm is a very good and proven option. It is not just someone’s whimsical idea.
🇦🇺

Miller carbon likes to trivialize many things that many people obsess over. I understand where he is coming from. On the other hand a 12 inch tonearm is only one option, and there are pros and cons. Anyway, no one here is saying that a 12 inch tonearm is per se a bad idea. We are just trying to find out why the OP is having problems with his new tonearm.

@amg56   Effective Length 282 mm = 11.1 inches!