That sounds about normal. The cowls Van's supplies are far from the super finished Gel coated ones that a builder can just bolt on. Mostly due to the large engine and prop options builders want to use. This makes a more generic cowl fit a large number of applications. The plus is it saves cost. The downer is a lot of work is involved in finishing it.
On my cowl, I fitted it as close as possible, not being too particular about the spinner gap. I paid more attention to the fit up and down and side to side. Once the cowl was fit to the engine and fuselage, I then concentrated on the spinner gap. I made to gap deliberately close during fitup. Then I layed in several layers of 9 oz. fiberglass cloth and resin in the nose of the upper and lower cowl pieces. When this cured, I reshaped the nose of the cowl behind the spinner to the correct gap and alignment. Adding the thickness inside the cowl allowed me to remove enough on the outside to get the desired shape and still not weaken the cowl.
It's fiberglass and you can do a lot with it with a little cloth and resin.
Roberta