Topping tomatoes

I am running a trial of topping tomatoes in a greenhouse. Rather than cage or allow the tomatoes to clime a string I am topping the main trunk and keeping the tomatoe plants shorter and bushier. One of the reasons is that our climate is very challenging and the ability to cover shorter plants with a frost cloth on those high desert nights in August that an drop to near freezing will hopefully allow vine ripening. So far the plants are producing well and the size of the tomatoes is impressive. Has anyone else played with topping their tomatoes?

Sorta.

I was experimenting with no cages or string also. Really I let them grow along the ground and then would jam a stick in the ground to prop up each vine, topping it if necessary. It didn't work very well. I'd say it was 50% worse than the best tomato production I've ever gotten, and about 30% worse than average. There we all roma tomatoes, so determinate.

I have been thinking of topping tomatoes as they hit the top of my string trellis, about 6ft up, where the sun shade fabric is. So I am interested in this post!

(I just put out 30% agribon fabric over my beds this year. The results have been amazing. Way less water used, way less wilt in the middle of the day.)

I have some Black Cherry Tomatoes (from SSE in IA) which grow like MAD, and they reached the top of my (8', probably 6'6" above ground) fence posts, after which I topped them to no obvious ill effect. Still had to manage the suckers lest they turn into a jungle. Haven't had any reason to try it on other varieties.

If you string a single stem tomatoes,  is it possible to trim the lower 2-3 ft to bare stems, curl them up in a circle? This way the whole plat would reduce in height for several feet.

I'm not sure -- are we discussing determinate or indeterminate varieties?