You've gone all week without a response?! This needs some more attention (adds 3 flags).
I've set up an 8' tall arbor, (12' long and 4' wide), so like you, I am most interested to see what combinations are going to succeed. Today I planted scarlet runner beans, 2 types of cucumber, and nasturtium. I soaked the seeds overnight, and put a lot of
biochar in the top 2" of soil. I've read where biochar reduces the soil albedo so that all that black on the surface raises the soil temperature. When I
water it this week, I'm going to grind up some biochar in the water. Soil temperature here is just creeping up over 60, so I hope I'm not pushing it too much to start this early and my biochar additions will help warm it up.
Later on, I plan to add some vining tomatoes, but those starts are still in the
greenhouse, and about 2" tall. I figure in a couple of weeks, when the other seeds are up, I can add in the tomato plants.
We have a problem with squash bugs in the spring time, so my plan is to wait until summer to add the squash (pumpkin) companion and use that as an opportunity to fill in any holes. I have some butternut squash seeds that have no problem sending out 10' vines, and now I have just the place for them.
Oh, and about spacing, I planted the seeds 6" apart and we will see how much thinning I need to do.