I havn't used Jarrah or Merbau on any decking as of yet. I did use Jarrah on a new timber gate which was made from a timber called forest red. I was very happy with the shade.Like all stains and timbers there are many variables and you can have two people with the same timber species be happiest with completely different shades. I would say that both new colours will be somewhere between cedar and what Flood call sedona ( what I would call walnut brown). Try calling Flood toll free in Sydney and twist their arms to see if they have any small samples on timber or can they send you a 100ml container of each new color. I think it will offer a more pleasing colour spread to the product range. Wish I could be of more help.
JimJ
www.restore-a-deck.com.au