John,
Details4Scale. They do a 16" and a 20" as standard sizes
I got one of their chutes in white for my DerJet Hunter. 16" diameter matched my 1/6 Hunter exactly. I had them add an extra slot (5 slot chute) to make it scale for the Hunter.
Don't be in a hurry though - mine took over 9 months, although the new ownership may improve things.
I scratch-built the installation, with a lite-ply box lining above the pipe, plus I 3D printed a combined single servo operated door release and chute release mechanism that works really well. The doors are spring loaded open and retained closed via the servo driven pin that also releases the chute.
I run it from a locking 3 position switch. The locking switch part came from an inadvertent in-flight deployment on finals at ~20ft that almost destroyed the model.
It's a tight fit at 1/6th scale - packing the chute takes a few tries to get it all stuffed back in.
It took a few tries to get the chute to deploy reliably - I use a fabric liner to the chute box attached to the doors that lifts the cute up as the doors open to get it to stream. Sorry, I don't have a picture of that and its hard to describe. You can just make it out on the rear-view photo.
Paul