My opinion on this for what its worth;
My Zed used to get parked up in a garage for 3 months at a time. I never bothered with trickle chargers or disconnecting anything.
I pulled up in the garage, left it in neutral, handbrake off. Couple of bricks to stop it rolling back or forward, covered, locked garage, went to sea.
Came back 3 months later, uncovered, got in, started first time every time.