I think there are some folks over at Ravelry who must have measured the 46" down the spine because there are a few Mara's that cover the butt and beyond.
Well, I'm sure not a fast knitter by any means. I really poke along with my "throwing" style. But I knit a lot of hours per day. I don't have a day job anymore, being self-employed and semi-retired at that! Plus, no little ones running around anymore. Kids all grown up, and their children all in school. No more babysitting. ;-(
I wish I had learned Continental in the first place many moons ago, cuz it's definitely speedy! But my tension is perfect with the "throwing" method....and since I'm mainly a garment knitter....cardigans, pullovers, vests, jackets etc....I don't want to monkey around with gauge.
You know the old saying: if it ain't broke, don't fix it!
Your Mara will be stunning. Very earthy. For blocking, if I was using your yarn, I'd pin it out on a firm surface and stream it, or mist it, or lay damp "squeaky clean" terry cloths on top...leave until bone dry...then remove pins.
By squeaky clean I mean rinsed twice or more in the washer, and no fabric softeners. All soap residue removed. All softening agents removed.
I wish I could do that with my cream Malabrigo, but like I said earlier....undyed natural Malabrigo.needs the added cleaning. No way around it. Bah.