Well, I can only tell you about my experience in my studio with my Monitors JBL, I have always run XLR to them no matter what! After doing a test with both I found the 1/4 inch input to be just a little too hot for my liking. Since then I have pretty much tried to find any adapter I could to XLR, That is until I finally got my board for my home studio.
I have been using a Zoom L-12 for a long time now, so that kind of takes care of ever having to find another adapter.
As a Zen owner I would tell you to find an RCA to XLR cable and be done with it, The 4.4 will give you a better signal level than the RCA, but as you said 4.4 where you are is difficult. Can you buy from sweetwater? O ask because I saw you posted a link, and not sure who's available to you.
Cheers!