Fixed or adjustable proportioning valve

[luvmyclassics]

Getting ready to start on the brake lines soon.

I have an f1 and am putting disc brakes on the front and staying with drums on the back.

Any suggestions as to whether to use a fixed or adjustable proportioning valve?

I like the idea of the fixed so I do not have to try and adjust the ratio myself. However, if I am better off with an adjustable valve, that is what I will purchase.

Thanks in advance.