Re: 5mm or M5/6 for Arches??
I've seen arches with both styles and think both look great, but I like the M5's better, they are viewable from any angle. It's true, the 5mm are very directional, but when viewed dead on they are very bright (much more than an M5). It's a trade-off.
I faced the same decision when making my mini trees this year and chose the M5's. Very happy with them.
X3 Ren48LSD, X4 Ren16SS, X2 Ren24SS, X1 SRen32, FM-02
X36 Super Strips, X9 Dumb RGB Mini Trees, ~25K lights (mostly LED)
~250 channels programmed with Vixen+ and run by Vixen 2.1