installed new brake light switch onA833

Heavier grade oil does two things maybe three.
1) it slows the gears down faster,and sometimes but rarely is that a good thing, and
2) It takes longer to get squeezed out from between the brass and the brake, making the shift take longer, and
3) IDK , I'm thinking. There has gotta be a number 3.
Ok here's one; when cold it helps prevent grinding into reverse by dragging the disc to a stop; 'course if you have the departure set right in the first place.........

I run the thinnest oil I can get away with for the fastest possible shifts; I don't want to see any breaks in the blackies, to indicate a shift. That is time spent not under power, and serves nothing but to slow me down......lol. Yes I'm kidding; I have 3.55 gears so first gets me to over 60 mph,lol. I should say used to.
I run 50/50 ATF and 75or80/90 . That gives the cluster pin enough protection to go at least 135,000 miles, maybe double that, cuz it was used when I put it in there; for all I know it could be an original 1968 pin.