I made MANY 450+ strings for Dan Quillian that he resold or put on his bows. I did a lot of testing with it myself and found dynaflight97 out performed it. On a FEW bows 450+ is quieter, but on most there isn't much difference. I personally would never mix materials. Even when I made Dan's strings, I didn't even use dacron in the loops. I used all 450+ and padded with 450+ only after having Dan approved it. I told him I was uncomfortable using dacron in the string because over time the tougher 450+ or dynaflight97 would still be doing all the work while the dacron is just a filler. He said that he only used Dacron in the loops instead of using the same materials because it was cheaper. The cost for a couple of feet of 450+ or dynaflight97 is neglegiable...cents.
I certainly wouldn't use dacron as a filler in the entire string. No offense to Ron, I respect his knowledge, but my experience tells me the dacron would stretch and the 450+ wouldn't...and in the end the dacron will at best do nothing that using all 450+ wouldn't do, and at worst will end up "looping around" the 450+ like a rope around a pole making for an asymmetrical string. It just isn't worth saving a few cents IMO. If you want 450+, use it without mixing it. If you want dynaflight, use that without mixing it. If you want dacron, use it without mixing it. I have made far too many strings to count and tested them far too much to disagree with my findings when comparing dacron, 450+, ff, and dynaflight.
Dacron is the slowest, then 450+, then ff, and dynaflight the fastest.
All are quiet on a quiet bow...but on a noisy bow dacron will be the quietest and ff will be the noisiest. 450+ is a tiny bit quieter than dynaflight, and dynaflight is quieter than ff.
Dacron resignates too much for me. I personally would never keep a bow that couldn't use a high performance string, even if that meant modifying the tips myself.
My favorite string to date of the materials listed above is a 3 ply 12 strand dynaflight97 string made from 3 bundles with 4 strands each...with the loops padded with an extra strand of dynaflight97 bringing the strand count in the loops up to a total of 15 strands...just requiring the addition of 1 strand per group. On a recurve, I might would pad with 2 additional strands per group, bringing the loop count up to a total of 18 strands of dynaflight. Serving only requires a few strands to be added between the bundles...mixed into the individual bundle groups by unstringing the bow and untwisting the bundles in the area of the string that the serving will lay over and then twisting this area back up so the "inlays" are smooth and the serving does not create a "bump" as adding it to the final string would do.
12 strands of dynaflight is quiet on all bows I would personally keep. If it won't shoot that quietly, I personally wouldn't keep the bow unless it was only for target shooting...but that's me. It is also the fastest I have tested while maintaining stability. I personally believe that when one goes to the extremely light weight strings, one starts to get less consistency in performance. Consistency = accuracy.