Flared tube v.s straight wall tube.

Hello to all,I am planning on going up in tube size within a month or so and have started to look at new tubes online,and would like to get youre guys opinion of flared tubes compared to straight wall tubes,I am not talking about the comfort flare that sits against the base of the penis.My whole pump system is from Kaplin and his tubes have that flare where the tube gets smaller as it heads for the top of the cylinder.I see most other tubes/cylinders are the same size diameter all the way to the top. Thanks