Hi sleeplessinCalifornia,
Blended talalay will be in the range of 30/70 to 40/60 (synthetic rubber/natural rubber) depending on who makes it (either Latex International or Radium) and both are good quality materials. The only other Talalay option generally available (made by both companies) is 100% natural and you won’t find a range of blend ratios like you will with Dunlop … it’s either one or the other.
With Dunlop on the other hand you will see a wider range of blends available but because of it’s general lower cost I would tend towards 100% natural Dunlop which is widely available (and in the same general price/value range as blended Talalay) and then go as low as about a 50/50 blend for a more “budget” latex alternative.
There is more about this in post #6 here (which includes a discussion about “organic” Dunlop as well) and a more detailed discussions about some of the differences between SBR (synthetic latex) and NR (Natural latex) in post #2 here (including some links to some rather technical information) and in post #2 here.
Phoenix