After building mine I would want to give you a little advice...
Make the mount an open slot, not a hole, No-one should have to remove their axle to mount a bracket.
The plate, at that height, without being angled up at about 20* is very close to the ground when mounted Horizontally.
I would not bother putting a bend at the top to hold the bracket from slipping dow like some people do, If it is slipping you have a much bigger problem than it hitting the ground BUT it will add some stability to the plate and keep it from vibrating or shaking.
What I ended up with ...


Make the mount an open slot, not a hole, No-one should have to remove their axle to mount a bracket.
The plate, at that height, without being angled up at about 20* is very close to the ground when mounted Horizontally.
I would not bother putting a bend at the top to hold the bracket from slipping dow like some people do, If it is slipping you have a much bigger problem than it hitting the ground BUT it will add some stability to the plate and keep it from vibrating or shaking.
What I ended up with ...

