Make sure to sight the shot with your dominant eye. Major mistake most players make. Im right eye dominant so when Im cueing I make sure to cue the shot with my right eye and not my left.
The biggest problem is training left arm not to move side to side up amd down. I dont remember How I controlled it with my right
I would concentrate on CB position play and not put myself in a position to have to shoot opposite hand. Then I would learn to use a bridge.
I've seen more blown runs, lost racks and lost matches because someone gets a wild hair and shoots opposite instead of getting the bridge. I'm on a team right now where the captain thinks he can shoot lefty and all the low handicap players follow his lead. We lost 2 matches last night because of this kind of bad decision making.
If your normal handed game isn't the best it can be in all aspects, then don't waste time trying to develope a talent you don't have fully developed on your dominant side.
Bartram Wiley and the like can switch up all they please, they have complete dominant hand games. Most guys want to shoot opposite because they don't want to use the bridge... It's easier to become a proficient bridge shooter than it is to become ambidextrous.
It sounds like you need a new team captain... or to jump ship and get on another team. I see these league captains all of the time who wear logo billiard shirts, own expensive break cues, jump sticks, cues, cases, logo gloves, (bla,bla,bla) ect... and think that if they look and dress like what (they think) pros look like, that they will shoot like a pro. Most all of the time these type of "players" will choke often on any shot over 6'. I'll play them for $$$ on my worst days anytime that they are willing to put their money down. Sounds like the guy is sacrificing the team while he is trying to show off at something that he can't do very well... or just likes looking like an idiot.
I'm a little late to the thread, but...
Here's a simple tip to start to learn to play off hand.
1. Use an open hand bridge. No need to start learning complex bridging.
2. Shoot 5 object balls into pockets (no cue balls yet) before you start warming up with your regular hand. You won't get too frustrated, and the break you receive will allow your brain to put what you've learned into long term memory. In other words, don't try to learn it all at once.
3. The things you'll want to focus on, is a smooth back stroke, and then the stroke through the cue ball (finishing your stroke). Try to keep your shoulder and elbow still.
So, 5 object balls (not using the cue ball) into pockets, until you start getting the feel, and the object balls are going dead center. Then start adding a cue ball. You'll be amazed how quickly you'll pick it up.