i use lower case for me and usually capitalise Him or Your when addressing him, but i do draw the line at W/we. i just think it looks silly, and there is something about it that seems kind of pretentious to me. We're all aware that we're doms and subs, i just don't see the need for it.
It's not a direct sign of respect like capitalising Master's name when writing to or about him. Just writing the usual we makes it clear that both the dom and the sub are being referred to.
Just my opinion, for what it's worth.