Hangar is on point. Diving and coming up through the bomber formation is the way to go. I used 70 to 90 degrees of deflection. It takes a while to get accurate cos your bursts are short, but you are less vulnerable. Great fun when you get it right. Allow yourself a week or two of practice. Trust me, it’s hard
This is where you treat is as a game. It’s not easy to line up for a specific place on the bomber. It’s very easy for the rear gunner to swing that MG and blast you. If you are talking about a formation w multi gun bombers, then its suicide. The 109 is delicate, the pilot is even more so. Better to walk away w a probable than to not walk away at all. The game is still the same…the object is to come home.
…which I should really do except when I do I seem to either run into the bomber or go sailing past way out of range…as @Maico said, it takes practice.
Another thing to remember is the Me-109’s cannon. That is your “bomber killer”. You should have a way to fire the MGs and Cannon separately (I don’t have the DCS Me-109, but seem to recall from IL-2 that it had that capability). It’s not perfect but to make the best out of each pass, when you get to a firing position, try a short burst from the MGs and if it looks good–like its going to hit–then a burst or two from tha cannon.
Very well put Hangar200. I just want to add that, Yes you have very little ammunition and you will miss a lot. But when you hit its catastrophic. The main thing is they miss you. As Franze points out, head on passes are deadly against bombers too. Again they take practice and patience.