Lionel Prewar transformers question

I am building a OO layout, as would have been done in 1938 using my 0080w set.  Back then, those came without a transformer but with a 166x whistle/directional controller.  What would have been the typical transformer sold by the hobby shop for that set?  I am guessing it would have been one of the smaller 40 or 60 watt ones as OO doesn't need the higher power ones to run.   The dealer demo layouts seem to have a 1041 with them but that is 45/46 so not correct, maybe a 1030 with whistle controller.  AD