@kicknargel Consider metal rings around the top so your rope pulls out clean without catching / hanging up.
Be sure to secure your rope, or have a second rope attached, so only the balloons fall and NOT the net. Dropping the net's a serious loss of points.
Is this on a stage or in another style of venue? The one time I did one in a space with a fly system, I basically followed the snow cradle concept. The only difference was that instead of holes in the cradle, you just drop one batten far enough that the balloons fall out over the top (or raise one batten to achieve the same effect).
I had to drop from one of those net-style setups once, and pulled the fishing line walking away from it. Problem is I didn't know the line hung up so I gave myself a matching set of friction-burned palms over the course of 50 feet. So....wear gloves. Or be smarter than I am.
@kicknargel You might consider a solid black cloth, rather then open weave netting, to prevent the balloons from being seen until dropped.
The aura of mystery and all / not blowing your load until the moment.
This discussion reminds me of the DNC here in Boston when the secret service locked all the doors to the catwalks and the people who were supposed to release the balloons were delayed in getting to their stations. Moral of the story is make sure you can get to your pull line!