Hi Andy,
Not sure what you mean by ''measurement between inside of two legs''
but centre to centre mine are the following -
Single hoop = 275mm
outside legs = 950mm apart
inside legs = 400mm apart
As I said these are centre to centre measurements, if you measure from between each leg this will vary depending on the diameter of tubing you use.
Hope this makes sense & is of some help.
Regards Phil.
