Erik! Put on an regulator directly! You will feel the diffrence!
This pump is made especially for use with double-weber-carburettors. It works fine, and my carb-mechanic at the ”bromsbank”, who adjusted the carburettors, told me that a regulator is not necessary.
But I will ask again next time I am there, as I need the new engine to be adjusted again. So perhaps we can test it with regulator then and see if it makes any difference.