Always variation 2 which seems a good choice to me. As variations generally increase in complexity as you move from 1 to 4 I find it good not start with the simplest variation, but no. 2 is a good choice. Then after the initial few measures at variation 2 I may go to a more subdued arrangement using variation 1, then the more upbeat arrangement in variation 3 and finally variation 4.

This is all just using the standard variations in MSA. In practice I usually build up what I want in panel memories, but I often start using the above selections.

Mike