Closure method on repurposed peapod?? install question

[Gsx-rboy750]

So the question is what type of Velcro or closure method would you suggest?
I have had this bizy for years collecting dust (as you can see from the color is was a 90s purchase however it is a quality breathable top and I don't do the bizy thing but after reading all the cleaver ideas here I decided to make a peapod until I saw this thing sitting.
Long and the short is I split the bottom to slip over the foot end and have debated where to cut on the top part. I do think I will make the incision above the purple seem.
My though was Velcro but then threw the idea of elastic and then thought about pull cord.

Basically I currently plan on using Velcro unless someone else changes my mind.
I also have the old down bag that went inside of this which I intend on making a underquilt/peapod insulator AFTER I have completed this. That takes cutting into down which I have no experience doing. However I will state I did custom upholstery for 10 years and spent more time on a "thread injector" then most.
Here are a couple pics.
Foot end (already cut)


Hard to see but this is the setup without the head stretched up.


My head end (again not cut) I intend on making the cut above the purple.


This is it as extended as possible without the head cut. I Am 5,7 so I have plenty of room.

[Scotty Von Porkchop]

hmm interesting .... the more I think about the less I'm sure how I'd approach it. keep us posted as to how it goes though.