Avoid long walking when changing between Tokyo subway lines

On my last trip to Tokyo, I made extensive use of subway lines (Tokyo Metro and Toei). Very often, there were no direct subway route to my destination. So I have to change trains. And since the subway had a bit of history and development, I have a couple of routes on hand to choose from.

I tried to pick a route with minimum walking distance when changing trains. But to know how much I need to walk when planning my trip was a challenge. I looked through the official websites and Wikipedia. No resource on the platform-to-platform distance were available.

When planning my trip, I tried to avoid interchanging between two stations with different names, or interchanging with "transfer at ground level", or interchanging at large train station. I believed these clues would hint a long walking distance. These methods might have helped me avoid some walkings, but I still encountered some long walks. For example, my interchange at Mitsukoshimae between Ginza Line and Hanzomon Line took more than 5 minutes, along a long corridor between the two platforms. Had I chose a different route and changed between Ginza Line and Tozai Line at Nihombashi, it would have been a 1 minute walk instead.

I know that there is distance information available at the direction instruction guiding passengers to the desired line. The problem is that I do not get to see it until I alight at the interchange station. In such case even if I found that the walking distance at that station is long, I hesitated to get back on the train and try a different interchange station.

Question: When planning my trip involving Tokyo Metro and Toei, how can I know how much walking is needed when changing trains?