I am currently reading a thesis on the warp weighted loom and she has surmised that multi-harness weaves are better worked with only one row of weights. I thought I would try it, since it sounded like she had experimented herself. However, having tied up the loom, with all new heddles, it turns out that it didn't work for me. The pictures and diagrams of old looms, show 3 heddle rods and it is thought that the bottom support bar acts as a "shed bar", helping the 4th shed being just open. This
I am using a stick shuttle instead of a weft butterfly, mainly because I sometimes need to travel with the loom and my weft butterflies keep getting too tangled to be of use. I don't think it makes weaving any easier.
It still isn't my favourite way to weave. I do like my floor loom, but it is very satisfying doing something other than tabby weave, which is by far the easiest way to dress a warp weighted loom and what the weave structure is of virtually all the projects on looms I've seen in real life or in photos. I'm sure there are project twills out there, but I just haven't seen them.