I've got one idea for smooth placement of walls in corners and one idea for smooth placement along straights.
For corners, I suggest you to use GR HMedit (
find it here!. There you can select each object and move/rotate it to have a smooth wall. It requires a little practise (make sure there is enough overlapping because there the walls are showed slightly too big) and quite a lot of time, but will give you the best results
for perfectly rounded walls (like a circle), you can also use
Snakeditor, but it's a bit harder to understand, I think.
For straights, I'd always pay attention that you have a "nice" angle to work with. I'm not talking about having like 30 degrees, but about angles like 45° (1px to left, 1 px to the top), 33,7° (3px to left, 2px to top), 26,6° (2px to left, 1px to top) and so on. You can get them by entering the size relation (e.g. in case of 26,6° it would be 0,5) into an ARCTAN of your math calculator (at least for me it works
). Make sure you don't have the radian measure activated.
By using angles like these, it will be very nice because it's also easier to make the other surroundings then. But maybe you should continue this one as it is now and consider it for the next track.
Btw, is it inspired by Circuit de Catalunya?