Here are a couple of differing examples, the problem being, that each type of weld has specific issues and characteristics. The answer must be subjective, depending on the particular situation / circumstance that exists at the time. An easy weld one day, may be a difficult weld the next. Any weld time comparison would have have to include a huge amount of relevent data pertaining to the situation and would have to be carried out under lab controlled conditions using all the methods available for each weld and then using all the currently available machines (each having its own characteristics), with reference to actual examples made in the real work place, that matched the criteria. And all this, under ideal conditions, with a skilled, knowledgeable operator ( each with their own characteristics!)
What is "possible" and what is "probable" and what is "practical" and what is "wanted" and what is "acheivable"...the five meeting together in a desired time frame is an acheivemnent..
" how long is a piece of string? " springs to mind...
I once tried to create a table for metal droplet formation on a wire tip, droplet deposition... The machine makes individual drops of known initial parameters.
I found there existed a window in which it was possible to make drops, using a chosen filler wire of known diameter.
Within that window, i found there were thousands of combinations of parameters ( including time ) that would produce a drop.
This was just for one filler wire type, using that particular machine and using my skill and knowledge. ( i mention that because it is relevent, it is likely that another skilled operative would achieve different results.)
Now, how to go about deciding the ideal for many filler wires in every circumstance and then, decide which set of parameters suited each and every joint, would be a lifetimes task without a cray computer..
I gave up..and carried on making drops, noting the parameters i found that worked well for a particular situation. I am a happier person for that..