As I mentioned above, I don’t think you need anything in the rear window since you have an unobstructed Liberty for upper rear warning. I wouldn’t go crazy spending a lot of money on the running boards; I consider them secondary warning since they’re so low to the ground (nice addition if you have money to spend, but not necessary for an effective warning package if you have other bases covered).
Aside from the grill lights, I’d focus funds on mid/lower rear warning, a HLF if allowed, & mid-level side warning (ie intersectors under mirrors). Also, it was hard to see in the vid, but it looked like you had the steps in the rear bumper? Some mpowers mounted in there facing sideways would help with rear side warning without having to drill on the bed body
Yeah, IF you had a PB, then I’d say to go with powerarcs on pedestal mounts if you really wanted a sweeping effect. The problem with oscilasers (as well as rotabeams and powerarcs), though, is that they’re super bulky & deep, so they’d look funny in this application. However, I think that M7’s will looks great on both sides of the Chevy ribbon (aesthetically and in terms of warning effectiveness)