@Quentin_Compson the above seems a good yardstick in terms of optimum times between shaves to figure these things.
I would suggest shaving every couple of days with a few blades of your choice, for in that way you will get the best impression of how individual blades feel and behave.
At a week + the experiment is diminished somewhat, because in my experience the blade is doing what any blade does best, removing significant growth. The distinction becomes blurred.
If a blade is tugging on a first pass on a 1 week growth, just discard it from consideration. A Fatip is a fine OC and will take no prisoners. It will be the blade talking.
If it's a 1 week+ shave the second or certainly third pass will give a more faithful impression of blade feel and edge if said edge is not adverserly affected by the significant beard reduction it's having to do.
I concede. Very good points being made here.