I did on my 69, but the others I didnt put a stop in. I thought it might be an issue, but so far it hasn't been. For as easy as it is to install, it cant hurt to add one.
I'm using a tilton on my setup. The 98-02 f bodies were notorious for horrible clutch hydraulics and lead to shifting issues. I used a Tick Master cylinder on my 01 WS6 to remedy the issue. Harder pedal feel and what some would say is too stiff but I got used to it. Instead of paying for the tick I found the tilton that they use and a conversion mount to use with the speedtech bracket and spent the same for all of it as a new gym master.