xps 8700 replacement heatsink/fan

hello all!

I'm looking to get a bit better cooling for my xps 8700 (already in a new case).  I know ive seen pictures of the stock heatsink/fan removed but im wondering what the full process is. ive read the manual but it looks like it doesn't cover the part where you remove the backplate. I believe it just covers removing the screws.

so question 1 - how exactly do I remove the heatsink/fan (picutres would be great! but I can figure it out). I do have access to the back of the mobo.

2- what weight cooler can I go up to? I know the stock cooler is only 250g and it very close to the mobo. would something along the lines of a 212 evo or cryorig h7 be too heavy at 540g? they are also tower style so that alone would put more stress on the mobo.

thank you!