I once owned a Glimakra "Aktiv" that had all the lams at one level, 2 per
shaft. It worked, but I can't say that it was decidedly better or worse than
having the lams at two levels. You still have the lams pivoting on one side
of the loom.
What does make a difference is to use half floating lams as on the Cranbrook
looms where the upper set rides on the lower shaft bars, or the Ulla Cyrus
where both sets ride up and down. The upper ones ride the lower shaft bars
like the Cranbrook and the lower lams are supported by two cords coming from
the shafts.

Sara von Tresckow, Fond du Lac, WI
sarav@...
Author of “When a Single Harness Simply Isn’t Enough”
http://www.woolgatherers.com Dutch Master Loom/Spinning Chairs/Öxabäck
Looms, visit us in Fond du Lac or contact us about your weaving/spinning
needs