I've set off for strats 6 times in a Mossie XVI.
First time, I didnt manage fuel, hit front lines at 20k and a P-47 spotted me, shot me down after a brief fight. Fair play. Second time, I was at 15k in my own territory when a 262 spotted me. This time I had managed my fuel and was able to evade him, had to jettison bomb to do so. Third time, was not intercepted but was killed outright by flak at 28k feet and 360 mph over strats. Fourth time, was not intercepted but got PW from flak at 29k feet, 360 mph over strats. Inevitable red screen and teleport back to tower happened 2 sectors later, still no interception. Last two times, made it to strats, made it past the "Magic-Mossie-PW-Flak", bombed city and landed. Second landing was post disco, so no name in lights.
Flak's biggest concern, will have to see the flak-kill rate after a few more sorties. With a bit of wisdom in fuel management and routing, the first dar bar I show which suggests strats comes when I'm near 30k, at full speed.