Looking at the way Slotman uses Radii I think all the curved track is expected to nest, as they do with Tomy where the hairpin fits snugly inside the 6", the 6" inside the 9" etc. The Micro Scalextric hairpin doesn't fit this formula, so I don't think you'll have much luck defining a hairpin and 9" bend in the same track system.
Can you create a second track system solely for the hairpin, as I think you can combine different track (so long as the lane separation matches) in a single layout? So the 9" bend would be radius be radius 1 in Micro Scalextric and the hairpin radius 1 in Micro Scalextric2?
Once you've sorted that try the Micro Scalextric obstacle track
I have to admit to using Ultimate Racer, where I have both hairpin and obstacle working
Can you create a second track system solely for the hairpin, as I think you can combine different track (so long as the lane separation matches) in a single layout? So the 9" bend would be radius be radius 1 in Micro Scalextric and the hairpin radius 1 in Micro Scalextric2?
Once you've sorted that try the Micro Scalextric obstacle track

I have to admit to using Ultimate Racer, where I have both hairpin and obstacle working
