As I hoped, very experienced advice!

tsl, if your dropouts are really 133, then it seems 135 would fit even better than 130, stretching only 1mm per size vs squeezing 1.5mm per side.

OP, how far apart are your rear dropouts? Or if you don't have calipers, does the quick release push the dropouts inwards, or are they already pretty snug to the axle nuts?

Does the Portland have a steel frame (or at least rear triangle)?