For cold setting a stel frame rear triangle I now use an old rear wheel nutted axle with just two large washers and a wheel nut on either side. I place the axle in the dropout with the washers next to the inside of the dropout and with the nuts inboard of the washers. I tighten each nut by the same amount until the proper spacing is reached. A string from a droput up around the head tube and back to the opposite dropout allows you to make sure each side is spreading the same amount.

To make too wide a dropout distance narrower put the washers on the outside of the dropout and the nut outside of the washers then tighten the nuts until the wanted distance is reached.

Cheers