Tattoo etiquette for when to ask for a sketch/design? Should I ask before my appointment or wait until I arrive? ?

I had my consultation two months ago with a talented artist who was booked until April. He took all my information and inspiration photos to design his own unique take on what I would like. (Obviously not going to copy another artists work). My appointment to actually receive my tattoo is on April 6th and will be roughly a 4-5 hour tattoo, but I'd like to see the design just in case there is a color or something I'd polietly ask him to change. 

I dont know if I should contact him before my appointment (like the day or two before?) So IF there is a small detail I'd like to be different, he could fix it before hand. 

OR 

Should I wait until I go in for my appointment and look at the design for the first time then? 

This is my first tattoo where an artist has fully designed it for me, and not just a small tattoo picked out beforehand. I dont want to seem pushy asking for an update before my appointment, but I also dont want to waste his time or upset him the day of my appointment if there is a small detail I'd like to change. 

What should I do?