Is there a gut E string that bows well?

First, I have to say that I am an arco novice, and if the problem lies in my technique, I hope someone will give me some advice.

My #1 and #2 basses are strung with gut. One has Gamut "Academie" E and A, one has Red Diamond E and A. Both have Lenzner D and G.

My #3 bass has a Spirocore weich set. I have no problem drawing a good fundamental note on its E string; and, I can draw good sounds from the A, D, and G of the gut-strung basses, with relative ease. But both gut E strings are prone to producing harmonics before I can get fundamentals.

So: Is there a gut E string that's better for arco? If not, is there a technique that will more surely draw a good fundamental? Or (option 3), should I bite the bullet and string the basses with metal E strings? I do love the guts for pizz.