5xCV instead of 10xCV

[UnixJunkie]

That would also make training models two times faster.

Problem might be: you compute mean and stddev over the 10 folds for each model.
Maybe, you will not trust mean and stddev computed over just 5 folds.

This being said, maybe you want to do iterated testing and do those stats over something like
50 repeats (e.g. we train/test on random partitions of 80%/20% and we repeat this 50
times for each model).