Is this correct?
 

I was told premix should be 150:1 fuel to oil ratio. Is that correct?

Yes, that is about what most people premix at. Many premix at 128:1 (1 oz per gallon) because it is easier to figure out /keep track of how much oil to add. I assume that you are talking about how much premix with no omp connected.

Werd. I don't like having my OMP zip tied open. I'm gonna go premix, but I'll probably get a gas can or two to mix in then use those to pour into the car. Just like a lawn mower. I can use a calculator to figure it out. Thank you.

why not just figure it out at the gas station...its way easier...it tells you how many gallons you put in...then just run the 128:1 ratio...couldnt hurt to lube 'er up just a lil bit more...;)

Dont go too high though.While I was waiting for my custom front cover to be finished,I was premixing in the tank and had a stock S4 OMP bolted up just running at idle setting(for sake of having the OMP system sealed up and complete)
The power delivery and topend was horrible.Felt like I was making about 8psi when I was actually making 14psi!
It was just too much oil fouling up the mix.This can actually cause you to go lean because in a given volume of premix, the oil takes the place of some of the fuel,and oil is NOT fuel.

Not to mention lower the octane rating.

NA wankels like low octane... another benefit of premixing.