The only detrimental effect that I know of happens if you overheat a spot to bright red and then hit the oxygen lever.

Lots of people use cutting torches for preheating because they are handy. They work fine but you will notice that a rosebud works better when preheating thicker, or larger pieces.
Both cutting tips and rosebuds burn the same mixtures; the cutting tip does not add more oxygen to the heated zone unless you pull the lever.

I do not know of any literature on the subject, maybe someone else does?

Chet

I see torch use as Chet has stated....Need to weld a material that is less than an inch thick, probably use the cutting torch head, but if you have a column with a 6" thick baseplate and 2.5" thick flanges, I would expect to see them using the rosebud to preheat the materials.
John Wright

You have to be concerned with draining the accetalyne bottle too quickly . I was always told to hold the tip of a torch 2" away from the surface as not to heat one spot to much . You might get the flame to spread out more and cover more of the part if you use less oxygen .