but I have 6 guards I train, so I use two position training. Do you think it's worth it to train all six, or just focus on three?
Keep training all 6. At our level, training six is the best way to improve our teams. 
Be wary of following advice from players from small countries who have never had to struggle in a D V. They get handed top division economic resources and don't understand what it takes to rise up from nothing with D V money. Usually doing the opposite of what would-be gurus from countries with less than 60 players is well worth considering.
Don't worry about the fans hating you. Build the kind of team you'd like to have and don't worry about where the players come from. That's what I'm doing and it is working for me.