masons mitre

I am going to order a new worktop but I'm unsure how much excess is required to do a masons mitre joint. I'm getting the worktop cut to size but I dont think they'll supply it with the masons mitre joint already cut. So I need to get the joiner to do that bit for me on site. My current...

I fitted my current laminated kitchen worktop about 10 years ago and it went ok but I was never fully satisfied with the joints which I never got completely flat. I am just about to install a replacement laminated worktop and would just like a bit of advice to help me get good level and...