This is the best advice.

Last two times I cut mine down I ended up selling the bike/frame about six months later. Make sure you really plan on keeping it especially if you cut it to slam the stem. Negotiating the sale any smart buyer is going to say they are going to need to buy a new fork to drive your price down.

As far as spacers above and below, most frame and fork manufacturer have specific rules especially for full carbon. Read the instructions. I've seen some say leave spacer below, above or both but it's best to listen to the manufacturer unless you want to buy a new fork