Anne,

I'll try to make this sound right.

I too press my Pleats prior to tapering. I also hold myself to the 1 yarn tolerance.

But please note that I say "Press" not "Iron".

When Barb Presses her Pleats it is the pressure she is creating on the fabric not "Trying to go through all those layers" that is important. It doesn't matter how many layers you are working with.

I use about 100 lbs of pressure when I press. Now, I have 3' X5' pressing tables on strong legs and can get right up on them using my weight to provide the pressure.

Barb does the same thing. OK, OK, Barb is a little tiny petite thing and to get 100 lbs of pressure she has to lift her feet completely off the ground and fill her pockets full of rocks. But we do much the same thing.
All that weight was bending the legs of a normal household ironing board.

What I want to stress here is that it is the heat of steam and pressure that sets the pleats, not ironing. So many people don't know the difference. I know you do but I just wanted to emphasis the point.