I have set up 2 2010 EVRRs with World Formulas on them. We used Burris 5 degree mounts on both. One EVRR was a 100cc chassis, that one we had to modify the mount a little bit to get it further over away from the seat strut. Im not sure if there is more clearance with the LO206. The 125cc EVRR we did not have to modify the mount.
When it comes to Tony Kart I was told by factory tuners to not under any circumstance bend or move the seat strut on the engine side. It is in a specific location. The seat strut on the opposite side can however be moved.
We first tried a 15 degree mount but seemed like the seat strut bolt got more in the way of the clutch and chain guard. With a 5 degree, it sat just bellow the bolt. But like I said this is a world formula, so a little bit different.