I am looking for the quietest but still fast string for my Widow.  I have done most everything else to get my bow consistently quiet without the results I want.
I read names of other strings but have no idea what they are.
What is the best string to use for shooting 750-800 grain arrows with about 69 lbs.

I have had the best results with Dynaflight97

That is what comes with the Widow right?

I can't keep that string quiet to save my life, although it has saved a few deer's lives.
I have done everything on the planet to no avail.

Try a TS Plus.. Bobby Graham (he is located in (Sponsor's Classified)can make one for you... it might help

I used a padded loop D97 on my Widow with bow hush and hush puppies and would get comments on how quiet it was.

Ya can't beat 450+...Van

The best results I have had came from 8 strand 450+ with 12 strand paddded loops and home made wool silencers, and a lot of playing around with my brace height. place your wool just above the fade outs of the limbs.

Where do you get 450+?

I get mine from Chad Weaver now At recurves.com
I use to get them from Leroy Carlson.

I've always been happy with the ones they provide.

Set of beaver balls and the stock string and it's super quiet.

Try a B-50 Dacron and if that doesn't do the trick, use the Bow hush yarn wraps and whatever string silencers work best for you. You won't lose as much speed as you will gain in quietness.

Exactly that !alike