Careful, the Stewmac ones are poor quality, some of the Kluson Branded ones have 6 mm shafts. Allparts do a nice 1/4" shaft "3-a-side" tuner set.
Check shaft diameters before buying. 1/4" eyelet type bushings are a bit thin on the ground at the moment.
You could also use an etchant solution & some shoe polish on your current tuners.