Just to add my 2 cents 
I too have the Ollie Baker style mainspring tool but mine was built by Joe Collins. Their one and only weakness I have found so far is on carriage clock barrels, The arbor goes through the barrel in the opposite way so unless you want to try winding the spring on the pivot end (which would not be a good idea!) you have no option but to do it by hand. Chiming clocks also have the occasional back to front arbor. Just something to be aware of.
Paul.
