just going by stats, the dragonscale or elemental LW can provide better chance of sales because these have +elemental resists on them. you can't find too much gear like this in the common lvl 60 instances.
but tribal mats are by far easier to collect. the time spent on easy tribal mats compared to the other two, should also be calculated into your profit of money and time.
the last thing i want to say is, i see more people asking for a Hide of the Wild combine (tribal) than any other high-level LW recipe.
for such a recipe, you can ask for a small tip and im sure the person will be fine with it.