On the subject of sniper knee plates... as Kevster can attest mine caused a fair amount of angst. So much that he got on skype with me to bare his sniper knee over the interwebs.
I tried using a heat gun gently but decided it would not make much difference in aligning/fitting. I would suggest not risking it.
I did think I had to trim my sniper knee some to get it to go on correctly. I was wrong. I trimmed a bit underneath the front of the plate to get it to sit nicely on the shin. It turns out that it would have fit just fine without trimming. Trust in the Rob that he trimmed it properly for you.
Here's a closeup of the the knee plate now:
Before glueing I fit my sniper knee in two steps...
First I clamped the plate with many many spring clamps to the front of the shin such that "A" was as as vertical as possible. Don't try to make it inline with the the front face of the shin. I had better luck with making it as plumb as I could. The front face may not end up being perpendicular to the floor after glueing, but it is an easier goal for alignment's sake. Make sure there are as many clamps on there as you can fit. Once you start fiddling with the sides of the knee plate the front will want to move around. I would suggest letting it move around a little for your own sanity.
Second I pulled the sides back carefully so that "B" seems to run along the same line as the top of the shin. It turns out that you only need to do this for the last inch or so of the plate side. The whole side does not run parallel so stop trying. This maneuver takes quite a bit of force and squeezing. If you look down into the top of the shin you can see where the sides of the plate actually becomes warped and curved (I don't think I have a photo of this handy.) Please dont be surprised if the sides are squished where you end up glueing and clamping. Observe what parts of the sides actually touch once the knee plate is in place. You may not need to spread glue everywhere, only the mating surfaces.
I made a mark with an exacto knife (sharpie will smear when glue gets on it) in the inside of my knee plate where the top of the shin hits. This let me know it was aligned properly once the panic and anxiety of freshly spread glue begins.
For glueing please do not use CA for the initial knee plate attachment. You need more time to get very pissed off at your clamps, so E-6000 is the way to go here. Make sure you rough up the shin and the insides of the knee plate sides before applying goop. I might have used 600 grit maybe?
After fitting, glue it on in the same order you fit the plate. Glue the front on first and clamp the living poop out of it. You may find that there isn't much surface area to glue the front onto the shin. That's ok. Just spooge it up as best you can, even if it is barely touching the shin. A well placed RT knee plate does not fit flush on the front.
Carefully fold the sides of the plate onto the shin with copious amounts of E-6000. The red shaded area in the image above is roughly where the sides make contact with the shin (I would go look at my knee plate to check but my son is napping in that room and none of you are here to help with a cranky baby.) I spread glue everywhere of course, but I'm pretty sure that red are is the only surface holding the sides onto the shin. Next: clamp clamp clamp and then add another clamp for good measure. Check your reference mark in the inside of the knee plate and slide it up or down depending.
Leave your sniper plate for 48 hours, or even more, to cure.
One side of my sniper knee started to separate a bit right before my last (and first) troop. I daubed a bit of zap-a-gap CA in there, clamped it for 30 minutes and moved on with life. All is well in sniper knee plate world now.
I hope this helps the other RT folks who end up wanting to melt down their sniper knee plate into a tiny little white middle finger and mail it to Rob.
Aloha,
-Eric