A mistake I will not make again: when installing inserts, the smaller arrows went in with no effort; the first few I did actually ended up with the wide end just a hair below the surface (easily filled with clear). Because of this, I didn't reckon there was any need to clamp those down while curing (unlike the large chevrons, which were a snug fit and needed pressure to go in evenly and stay put). Well, turns out a few of my clear arrows down by the flippers rose just a tad. Not a lot, and generally just on one side, but enough to raise concerns about eventual keyline wear. So, TAKE NOTE: things can move while the epoxy is curing! I wouldn't have thought so, but apparently it can happen. So clamping a block over *all* inserts while curing is a good idea.
I wanted to correct this if at all possible, of course. Using a heat gun, I warmed up the underside of the insert until the insert face felt hot to the touch (corresponds roughly with when the plywood underside starts to look toasty.) Quickly, while the epoxy is still gummed up from the heat, I clamped a small block directly on top of the insert. The epoxy isn't soft enough that you can press the insert down by hand; you have to clamp it down and leave it until things are cool again - the longer the better.
Vid showed us that 12" black C-clamp from Hazard Fraught Tools early in this guide. I went and bought one, and it is a good tool to have for installing the inserts. However, its construction doesn't allow for much pressure. For hard to reach spots, I used this Vise-grip style clamp made by Kreg tools. It applies lots of pressure even at a 12" reach and is saving my biscuits right now.
Of course, I'm just crossing my fingers that the inserts don't rise again once the clear goes on...