I am leaning towards (Threefold Bolt / Sixfold Bolt) and (Explosive Bolt / Explosive Rivet) combo because those two are of opposite elements. Therefore, creatures that are immune to ice-elemental attacks (Frostwyrm, for instance) will take damage from Explosive Rivet which is fire-based.
But if this is a poor choice, I would like to hear about it.
The magickal gleam one doesn't really do much, just increases the duration. I have a band with sixfold and MG and have stopped using magickal gleam. I only had it to stun maneaters. Also I used it to light up the helixes, and to maybe hurt the wraiths if I actually hit them with it.