In addition to the above, there's no benefit to having a fully equipped training group. In other words, your Toyohara Ku K-2 A6M2 group can train adequately with 2 aircraft. If you divide it into A/B/C components, you'll have to take care to not populate the max. number of aircraft.
Also, you do tick up the training percentage to 100%, drop the range to 0 and lower the altitude to 5,000-10,000 feet to keep fatigue low, right?
I'm in your ballpark. Training @ 100%, Range of 1, ALT set to 10k except for the DB which I set to 11k. I swap out front line AC in the training groups for older models. As an example, for IJN fighters, instead of using Zeroes my naval aviators train with Claudes. I seem to remember somewhere that the more AC in a training group the better for increasing pilot stats so I run a full complement of air frames for my training units.
Bye for now,