In my experience you need to remove the crank to put in a rope seal.
The two piece rubber can be put in without removing the crank, just oil pan and bearing cap.
There is a tool that is used to install rope type seals with the crank in place - although it does usually require loosening all the main caps and allowing it to drop down a little to give more room. I have done it both ways many times. Installing one with the crank in place with the engine in the vehicle takes a very skilled and patient craftsman. I remember having my first experience with this on an old Buick engine when I was about 18 years old.
