No. When trellising them (as I did at home this year) I just train the vines across the top. When letting them trail across the ground (as I am doing on a rural site) I just let them roam, and turn the longest runners back toward the center. The first set is always on the main runners.

If you pinch off the tip though, it will just encourage the growth of new branches. Those branches will bear later in the season than the main runners. In long-season areas, that delay may not be an issue; but it would diminish my crop if I tried that here.

Wish I could post photos; the trellised Tromboncino is a seed crop, with the fully-grown squash held up with slings. Grown straight, they are really eye catching.

Thank you so much for your helpful comments. This is a new variety of squash for me, planted late in the season. Doubt I'll get any fruit set this late in the year. Just wanted to see what it looked like as it grows and found it grows fast and the leaves are huge! :-) Will try to redirect it across the top of the trellis.

You might still get some of the zucchini-like immature squash. In my location, Tromboncino is triggered to a burst of female blossoms late in the season; there are a lot of young squash set on my trailing vines right now. I pick them when about 1" wide... if you keep picking them at that stage, the vines should keep producing until frost.