It's not that complicated. Just fire in sets of two, when a weapon jams you switch to the other set. Been done before on an Annihilator, but I didn't see it for this beast yet. In keeping with the title, I stripped the armor from the arms. You can obviously move a few points out of the legs or head to put in the arms if you like, but then the title doesn't fit. Of course, you can also drop the extra DHS and put a half-ton each back into the arms, if you're interested in using them as shields at all. In the end, this build has so much face-tank-time anyway, I don't think shield arms are going to be all that useful. You can also get an extra 2 tons to work with by dropping to a STD280, if you want more ammo or armor or both. This is probably technically the more optimized build, unless you really care all that much about ~3 kph.
I don't own the Sleipnir yet, so I haven't tried it. In my experience running dual-RAC5 on a Jagger, though, there's usually about 30% of your heat bar still left by the time one of the RACs jams. RAC5s jam quite quickly, and take a long time to unjam, at least compared to RAC2s.
This is both fun and surprisingly effective - just don't ever fire all four at once, however tempting it may seem. Like you say, pair the RACs left/right and switch over as soon as you jam. The heat levels are pretty high when this happens but switching sides for even just another few seconds extra sustained rotary pain before you cook is the key to this build. Judicious cool shot use is, unsurprisingly, rather effective. It makes a nice change to the heavy gauss/quad LB affairs I've been switching between.
