I use a cloth tape measure to sort through stuff on the rack. If you have been wearing your wife's clothes you should have a good idea what to measure. Usually the shoulders.
While I don't usually use a cloth tape, my wife uses one a lot. Both of us know our sizes. We also take things home and try on. We like it because we can take our time. But, we live in an area with a lot of shopping.
The crossdressing community is one that needs to stick together and continue to be there for each other for whatever one needs. We are always trying to improve the forum to better serve the crossdresser in all of us.