The best "over boom" awining I ever had (still own it, actually) is not the pup tent, but similar. It is rectangular, with dimensions
L = (mainsail tack to clew)
W = 115% Beam.
Athwartship are four batten pockets sewn in to take ash battens - one forward, two in the middle section, and one aft. Each batten pockted was sited to lie approximately over a stanchion. A short 3/16" mm line is spliced at the tip of each batten in a grommet in the closure flap. This line attaches to the top of a stanchion with a round turn (to prevent sawing in the wind) and a midshipmans hitch (for adjustment).
The beauty of deploying this awning is it overlaps the deck; each batten tip lies about two feet off the stanchion so there's about a four foot crawl space; and it looks great in its arched appearance. Because its arched shape provides tension, it is not so prone to flapping in a breeze.
Its rolled up shape is a nice, tight sausage. And this makes it easy to deploy - just throw the roll over the boom, fasten the mid-line around the mast
, roll it along the boom, make fast near the clew, and tie down the stanchion lines. The awning can be tilted to port or stbd by adjusting the stanchion lines to allow for more shade.
Best of all, this is easy to make. It's two-dimesional and can be run up easily on a commercial sewing machine
. The battens take a little sourcing and experimenting to get the scantlings right.