Personally, I tend to use the same core of 13 or so instructions in a variety of different formations. High line, closing down much more, more direct passing, be more disciplined, Attacking mentality. If a player doesn't fit into said formation, I generally look to sell him. Occasionally, when looking to grind out a result, I'll revert to an ultra-defensive 4-1-4-1, but not often.
Stephane Bahoken is fantastic. Signed him for Sivasspor from Strasbourg for 300,000 Euros in my first season (transfer listed) - scored 20 league goals straight off the bat in the first season. Tore up the Turkish Super League - excellent shout for middling teams.