Tube currents and preventing them is not the only part in this. Not letting your scope get hot is better, HOW your scope cools is another, and if you keep your scope in an observatory then how it is constructed and painted are other considerations. Even
where you set up has a major impact!
Professional observatories don't have these issues as they are designed not by the astronomers, but by engineers, opticians & technicians whose job is to anticipate these and design so that these issues are not problems for the final scope and structure. Only us amateur astronomers do it all ourselves...
What all this has to do with spotting the Cassini Division? Little and a lot. It is all just a part of instrument handling before you even put your eye to the eyepiece.
But don't get too anal about this. It is very easy to get very pedantic about everything being "perfect". Getting too carried away with the "tech" part can take away much of the fun of astro for many of us. If you are new to astro, just get under the stars and run up some miles.
This is more important first up. Then you can look at measures that suit you and where you want to go with astro.
Alex.