I just put a pair on to use in my first century and was concerned also. So, I went to a place with no traffic, straight road, and level, to try them out. In my case it was a dam across a lake near me that is closed to traffic and is 1 mile long.
My entering approach that works for me. is one arm at a time. My exit is the same way. It did not take long to gain confidence and I can now even change gears and brake with one arm left in the bars.
Every now and then I forget and do something stupid causing a sudden move. You are essentially driving with your elbows and you really have to pay attention.
If I get around anything, other riders, passing traffic, dogs, or whatever, I get out of them. You cannot change direction or stop very quickly when in them things. ANY danger and get out.
I have not crashed yet!!