I know exactly what you mean by conserving space. For years I was
hearing "Get a 4 x 6, you'll use it all the time", but I thought that I
didn't have room for it. I bought a Porta Band and built a stand for
it. It hung on the wall when not in use.

Then a neighbor had a 4 x 6 which he offered to give me. I couldn't
resist the freebie and found a spot for it in my "stock room". I built
a stand with storage underneath to minimize the space lost. It is
great! So much better than the Porta Band! Get one and *find* some
space for it.

Re vertical mode: I built a permanent "table" for my 4 x 6 that is about
2" x 2". Being that small, it does not interfere with horizontal use
and is enough for vertical use. For vertical use all you *really* need
is enough "table" to resist the cutting action and stabilize the work.
I use it in vertical mode all the time this way, whereas if I had to
convert it, I wouldn't do it nearly as much.

Bob