Start with a spare piece. Try two medium coats and see how you like it. When you have a look that suits you, then you can do your final. I personally now do one heavy coat, but I am hitting a small screen cover and I think a heavy coat would not work for your large area. You will have to remove the covering from the display as it will be too dark otherwise....there is a darkening film over the display and it should be obvious if you have looked at it much. The film on the large screen is a pain to remove, but it comes off and you can remove any residue with alcohol.
and I'm not skilled in metal work or wood work unfortunately. It's easier for me to retrofit into something. So far I've put dna40's in two Vaporflask clones, and upgraded a Valhalla to dna40 which actually is a powder coated hammond 1550p and that is a super nice tiny little box. 
