cheers thanks for the advice best order a stack load more slide blocks then mounting is no sweat as i can put them on to the rail and then just slide it strait on to the aluminium. Next job i think is to make sure it is all perfectly level on the floor and get a plate made up to bolt the carriages too. If i can get the plates laser or water jet cut do you think i can rely on there accuracy to get the two carriages to aline or do i need to factor in adjustment with a oval hole or something?

many thanks again