Sadly Dragon's instructions aren't that good anyway so even if they referenced Tamiya colors, you can't necessarily go by them. Plus most of the Gunze colors are gloss.
If you have access to books like this from Osprey they are a huge help, even if you have to buy them mail order... One or two good reference books are life-savers. Failing that, try googling pictures of German reenactors. You have to watch some of what you will see (things like redyed modern Swiss uniforms) but usually the accessories and overall appearance are correct or at least better than crude kit guides).
Some basic colors for the figures using Tamiya shades
Helmet - field grey, dark grey, or field-camouflaged
Jacket - field grey
Trousers - field grey
Boots/shoes - worn black leather. shoes would have dark khaki
anklet covers.
Belts and Straps - black
Ammo pouches - black leather
Gas Mask Can - field grey or green painted metal, khaki strap
Canteen - brownish-green felt cover (field grey + earth) with
painted metal cap (field grey, dark green, black, etc.) and
black or brown leather straps
Mess Kit - painted aluminum, dark green
Entrenching Tool - black or dark brown leather scabbard, natural
wood handle, blade - natural metal or worn painted black metal
Bread Bag - faded khaki, buff, etc.
The flame thrower was probably grey or field grey. You can probably google up some pictures of it and the mine detector