Spindle sizes have been mostly standard for the last couple decades with the exception of a Shimano "Aero" pedal and different threading. Keep in mind the left one will be reverse threaded. One can get used to clips but there's definitely a learning curve. Grant Petersen, the polarizing head of Rivendell bicycles, advocates using platform pedals instead of clips or modern 'clipless' pedals. I'm a big fan of the Japan-made MKS touring model.