I use straight lacing for bals, unless the gap is super wide, or for some other extenuating circumstance.
I use cross lacing for bluchers.
I might use over under cross lacing for either bal or blucher, but this only works if I have even number of eyelets (not very common), because I have to start the lacing on top. Kind of OCD. then again, so is this whole thread, hehe.
Here's an example of an exception where I used cross lacing on a bal. The gap is pretty wide for some reason, I think this looks better than seeing the mess underneath.