My understanding of "rubber in the round" is not tit related at all as mentioned in various posts. It's when the cloth is stretched on the rubber near the corner pockets, it's pulled a little tighter to get the facing smooth, which tends to round the rubber a bit as it approaches the corner. This allows for a different angle that aims back to the cross corner pockets. (You don't see this as much for the side pockets because the cloth is folded more often than not on the facing).
If you hit the tit you're in trouble, it should be hit above the tit to where the rubber is rounded slightly, which varies on each table because the cloth is stretched differently and different rubber may be used. You should experiment when playing on a new table as how far up you can go to still make the shot, if at all.
Although spin will affect the direction of banks, when a ball is on the rail like this, it's accuracy in hitting just the right spot with the right speed that makes this bank.
Dave