This will use both trinkets at once if both are available, or either one if the other is on CD. It will show the tooltip and CD for the first trinket only.
Code:
#showtooltip
/use 13
/use 14
This one will require you to hit it twice if you want to use both trinkets, but it will show the first trinket and CD until you hit it once, then it will show the 2nd trinket and CD. When the first trinket comes off of CD it will show it again. I haven't tried this macro before but I believe it will work.
Code:
#showtooltip
/castsequence reset=[CD time of first trinket in seconds] 13, 14
hope that this helps.