I find every piece in a stick has a significant effect, which is why I like to start simple and work up.
A few blending thoughts:
1) Sometimes 2 ligeros instead of one seco, one viso, one ligero, works great. So if I'm low on visos, I'll try a different ligero in the viso spot, and get good results. This could be construed as a 1:0:2 blend, but I think of it as a 1:1:1 if one of the ligeros isn't overpowering strength-wise, e.g. a good Dominican.
2) I tried all the Dominican secos at LO, and surprisingly the "Piloto Cubano Volado" had the most rich flavor; richer than the Olor seco, PC seco, and also the Honduran seco. Most people probably see volado and think "no flavor." In this case it's not true. Unfortunately they are currently out of that. Fortunately I have a nice supply. They say it's "on the boat."
3) A single leaf of WLT Nicaraguan Habano Seco (also currently unavailable, of course) can add a little "something" to a mix without messing it up. It's kind of a magic spice leaf but not necessarily the best leaf for the full seco portion of a blend.
4) I use the olor seco as my binder; and I've been reading up a lot lately where I notice this is actually typical for top Dominican sticks: Olor binder, PC filler, which is exactly what I stumbled onto. One thing I haven't tried yet is the LO Olor ligero. While Olor is theoretically milder than PC, I'm going to see how the Olor Ligero works as the viso portion of a blend.