I don't own an SWK Heavy, but do own 2 SWK Standards. I also own 2 of the TKN "16 oz" PV's.

The TKN Kilts are a 65% PV 35% Acetate blend. The cloth feels quite robust and durable. Certainly more durable than Acrylic, but not as durable as wool. Be careful pressing the PV as it will melt it exposed to a hot iron.

Given the choice, if the SWK Heavy was available in the tartan I wanted I would take that route, but I have no problem recommending the TKN kilts.

Chris...