This might help:
https://www.msrgear.com/blog/stove-f...reign-country/

I am not familiar with the Omnifuel II, I have the original Omnifuel. I suspect they are about the same.

I was unhappy with it on Kerosene, but it did work. Primus said it would work on Diesel, I tried it on Diesel Number 2 (not sure if Diesel Number 1 or 2 are sold as such in Spain), it worked dismally poor on Number 2. I suspect that Diesel Number 1 which is closer to Kerosene specifications might work better. Jet A might work too, but I suspect you have no source for jet fuel.

When I used Kerosene in it, I found that I had the best luck using one part Coleman fuel and two or three parts Kerosene. That mix primed much better than straight Kerosene. When I used that mix, I used the Kerosene Jet, not the white gas (or I refer to it as Coleman fuel) jet. If I recall correctly, the Kero jet is marked 28, the gas jet 37 and the butane canister jet is labeled 45. But, since I have the original Omnifuel and you have teh Omnifuel II, maybe the jets are different?

As far as I know, there is no Jet for Alcohol. Alcohol can damage some plastics, and I have no clue if Primus used parts that will not degrade with alcohol, thus I would avoid alcohol unless Primus specifically says it is ok to use. If Primus says alcohol is ok, they might suggest a jet to use.

Most of my Kerosene use was in a Optimus stove, not the Primus, and I frequently clogged up some of the fuel passages in the burner head and had to disassemble the stove for unclogging. Overall, I think I have only about 2 or 3 more liters of kerosene remaining in my kero fuel can, once I have run out of Kerosene, I plan to just use Coleman fuel instead. i can buy kerosene for less than $4 USD per gallon but it is not worth the hassle of clogged up stoves, I plan to switch to Coleman fuel only after I run out of kero.