PS: I use paper presets defined by the driver, so they should have the right size.
I had a 44" print page width that fitted HM Photorag 44" perfectly till the next batch of rolls that were slightly smaller (possibly drier).
The presets will do their job as long as the roll width (and roll width measurement) behaves accordingly.
BTW, the PS3 driver behaves different and more stubborn on this issue than the PCL3 driver. At least on a Windows machine.
With the PCL3 driver I select a shorter length than width, I give the OK, the driver warns, I continue and set landscape in the driver main menu.
It will print the print page in landscape mode as long as the length of the print page doesn't exceed the roll width. The print page will have approx. 5mm print margins in the application to print from so at least 10 mm less than the roll width.
With the PS3 driver the margins are taken out in the driver, a print page specified in the driver has the netto size and no further margin reduction is seen in the application you print from. That way it could fit differently in the roll width. Any chance you print with the PS3 driver to a Z3100-PS machine? Reduce at least 10-11 mm on the length of the print page to get it in the width of the roll.
Also try to make a default or printing shortcut of the settings you want, the drivers sometimes go back to the default when temporary changes are made.
met vriendelijke groeten, Ernst Dinkla
Dinkla Gallery Canvas Wrap Actions for Photoshop
http://www.pigment-print.com/dinklacanvaswraps/index.html