Nat. gas heater stove flame level efficiency question

Motorapido

I installed a freestanding direct-vent natural gas heater stove in my rural, northern vacation house as the primary heating appliance, and I'm new to this type of heating device. It's a Kingsman stove https://kingsmanind.com/kingsman_collection/fdv451/
Question: There is a control knob that allows you to adjust the flame from tall to short. What is more efficient -- a short flame, burning longer with fewer cycles or a longer, bigger flame burning for less time with more stat cycles? Coming from experience as an owner of an oversized natural gas steam boiler, I assume that setting the flame level to the low setting and running fewer, longer cycles is more efficient, but I'm new to this whole gas heater stove world. I know that at the end of the day, the efficiency difference between the two settings is probably only the price of a six pack of beer over the entire heating season (see -- I technically did not discuss price, per forum rules), but I'm interested in knowing the science of the whole question.