3545 brakes

I have put the whole new brake system in my 3545. master cylinders everything. the cylinders are made by frogokov. what brake fluid do i use i want to use the best quality one i can get. what shoul i use and what grade???

cheers

DOT 4 works with everything, but for some older systems it may eat away rubber O rings. (brake fluid is very agressive on its own and can be used as a paint solvent)
Since you replaced all cylinders with new ones with modern rubber, you can use either DOT 3 or DOT 4. DOT 5.1 can also be used but DOT 5.1 is not based on glycol but on silicone, so dont mix these.

So which one should i use? i went to my autoparts dealer he has dot 3&4. dot 5.1 but which one would you recommend

I would use DOT 4 because it is commonly available at every gas station in town.