It has been a long time, but here is 3mc_training_v3.
This time there are two versions of the map included(day and night). The day version provides high visibility and is closer to the original and version 2. The night map dramatically reduces visibility and helps train closer combat.
Send any suggestions/compliments/complaints to firstname.lastname@example.org or add me on Steam; email@example.com and invite me to play on your server.
Credits go out to the author of the original 3mc_training.