Thanks for the input, Franco and OM, it was all very interesting feedback and insight into how these things work.
I like the look of those titanium shepherd's hook stakes, but I'm pretty happy with my Groundhog stakes. They always live in my pack if I ever need to make an emergency shelter out of my tarp, and I like how aggressively they hold onto the soil, and their red anodized colour makes them easier to see.

I will be picking up some finer cordage for the mid-tie downs here soon in order to make the extra tie-downs functional, I think the added stability and wind resistance is worth the few extra grams it will add.

After viewing the Rainshadow II setup video you posed OM, i skimmed the other videos Franco offered as well, and got a better idea from them as to how the setup for the floor is intended to be. As far as I can tell, I'd been setting mine up slightly wracked and with the front stakes at bad angles, causing the sides of the bathtub to tip down and spill out from under the fly. Watching how you set up the RS tent, it seemed evident that the key is to get those front corners set up right, and the rear hoop properly tensioned, that is what gives the bathtub its shape. From there, the trekking pole(s) really just give the upper elements backbone and angle.
A little more practice and noodling through this, and I believe I'll have it down.