Went to make my first small box to start off the level and the QIX enter'd the box right as I square'd off to the border 98%
This was the NES version by the way.
33x1000
My new stragety now is, I try to make a small "L" shape of thin walls in the corner, makes for alot upper 80 to lower 90's percentage's. Though the QIX won't always enter the corner as plan'd :P and the programers were smart enough to add those's line chasers if you take too long.
Just thought I'd pass that on, though I'm sure QIX fans may have been doing this for years.