Similar thoughts to Pete.

Ablaze 1's are too dull in my opinion - unless you had a game with heaps and heaps of white inserts.  I generally have used the Ablaze 3's everywhere and am happy with the results.  Appreciate that some people may not like them on GI - but i think they are great - i tend to colour match some areas of GI (to the surrounding plastic) as it tends to give more definition to the plastic and a nice glow/light behind stand up targets etc.

Best colours in my expereince to colour match are blue, green and purple - orange is probably worth matching as well.  Red makes a bit of difference, but not much, yellow looks much the same with whites or yellows.

For the backbox, its can change from game to game in my opinion - i reckon doing mainly white but then highlight one or two features with blue or green works well.

Flashers are blinding with LEDs - probably not necessary