No pattern for Lobster yet?
I got safe one to around 40-50 shoots but it's really hard to count em unless i monitor their address in cheat engine with W.
Here what i do to get to 40-50 shoots. Might eventually make a video clip if you can't do it but i doubt.
Upon start fire 7-10 shoots and stop holding the stick Up. Holding up is vital cos boss charges straight towards u and pushes u back, if you don't hold up you get stabbed by sword. But if you do hold up you avoid the sword somehow

that's 100% to start the boss everytime.
Then he withdraws backwards you can still fire shurikens on him, the boss charges two times towards you and swings with swords. Those 2 times you can avoid the sword by just jump before it swings-that's also 100%. After every swing he withdraws back few steps you can use the time to fire shurikens, you can even shoot him when he charges towards you but don't shoot when you jump. Cos if you hit im in the head the pattern is lost and he starts charging towards you pushes you back and kills you(lever up) won't save this time

.
So if you do all correct after initial charge and 2 swing charges you will get to around 40-50 shoots.So far this is 100% safe and then i got stuck and can't find safe way to continue.
I even managed to jump over it few times but its very tricky timing and it's not 100% and running away from him and counting shots is very hard...