Another gear oil question

I'm sorry if this aggravates a few fellow members. But I'm here for advice.
My 2009 Taco access cab has a 2.7 liter and a stock 5 speed stick.
The truck has about 80,000 miles on it.
At 50k I first changed my gear box and diff oil. I used MOBIL 1 but after about a year, I swapped it out for REDLINE MT1 because the MOBIL wasn't rated for brass synchronized trannys.
The REDLINE has now been in for about 2 years and I've always had at least some difficulty engaging first gear from neutral or reverse.
I replaced the shifter bushings. This stiffened up the gear lever feel. But did not help with the difficulty in finding 1st or reverse.
What gear oil have you yourself used?
Does it specify that it's safe for brass synchro rings?
I'm not happy with the performance of the REDLINE.
And I believe it is the cause of my shifting issues. Because it wasn't there before.

 

One trick that might help is shifting into third with the clutch in, shifting back into neutral, let the clutch out, clutch back in and shift to first. It’s worked on clunky trannies of mine in the past. Seems to get things aligned.

 

That DOES work.
Is that my only option?

 

Maybe there’s an additive you can dump in?

I would try replacing with a cheap Dino GL4 and save the redline in case you want to switch back. Won’t cost you much.

 

When I had my 2008 Taco 5 spd, I put Redline oil in the trans and didn’t like the way it felt. The shifter felt very notchy compared to the oem fluid. I left it in and got used to it, but I was disappointed that it didn’t improve the shift feel.

Edit. I used MT 90, not MT1

 

Correct
Its MT90

 

This is what I have in the truck.
I was incorrect.
On paper it sounds great!
In practice it's not as smooth as OEM.

 

@Pablo8

 

A buddy of mine swears by VALVOLINE Synchromesh. It has his clapped out 1999 gen one shifting great and no more grinding.
However, it's like 30 weight.
I'm not sure it's going to provide enough protection for my bearings. Etc.