I like the concept of the chicane on the parallel straight immediately opposite the starting grid , not least as it give main grandstand spectators more than just half a second per lap of action.
There is one thing though that immediately jumps out. If running the Yellow and green circuits, there is a barrier that would have to be really shortened. As it currently stands it's a very very narrow point on the circuit.
The right hand arrow shows where it should begin to curve, with the left hand arrow pointing out approx where it should meet the other barrier.
Actually taking another look, I'd amend your design slightly with the pit entry as well. the circuit width stays the same, but it's a larger and more inviting looking I think now...
