I'm glad that the down & down has worked for you, but the setup recommendations I posted are from Greg Frick of Inland Empire Driveline Service, not "just another guy" in my opinion. Down and Up doesn't take away the working angle of the u-joints, they are both still going through their gyrations but with the angles equal and opposite the harmonics in that motion cancel out. The problem with a mis-match is that the forces developed during rotation can compliment each other, adding together instead of cancelling each other out which leads to vibration you can feel, and increased wear.

There's a huge difference in setting up the driveline for a highway cruiser compared to a quarter mile warrior where it's common, accepted and correct to account for the wrap of the rear suspension during launch and max acceleration. Equal and opposite puts the u-joints in a bind in that situation, and with the high power, torque and bite leads to broken parts. If it were me I'd go back to that "older gentleman" and pick his brain a bit about exactly what he did, and the rationale behind it but if it's working it's working, right?