I have several brands of blades that work in anything I put them in. I never cared for this blade in that razor and that blade in this one. It was just never my thing. I tried to do a couple of runs of blade testing, and I could never get into it after I had found some brands that always worked. I can see why it keeps thing interesting if it's what winds your clock, I guess.
That is pretty much what I do. I use my Feather AS-D2 when trying a new blade for the first time. That razor won't bite too bad if the blade is rough or super sharp. If I don't get a great shave with the blade I will try the same blade or another from the same pack in a more aggressive razor (Rockwell 6S-base5, Slim on 7 or 8, or a Gillette Old Type). Usually though I can tell if the blade will suit me with the Feather razor. If I'm testing a new razor then I pretty much always start with Gillette Silver Blues. I stick with that until I get a good feel for how it shaves. Then I might try another blade to see if it works very differently. YMMV.
When I get a new razor, I immediately put the almighty Astra Superior Stainless in and see how it shaves.
For me, the perfect sample pack of blades to test a new razor consists of Israeli IP, Personna Lab Blue, PolSilver, Rockwell and vintage Gillette Platinum Plus, possibly followed by Voskhod, GSB, Nacet and Gillette 7 O'clock. Why? Because I found these blades worked well enough for me in the razors I already owned that I have about 400 IPs, 200 Lab Blues and 100 each of the PolSilver, Rockwell and vintage Gillettes laid by. And I have a tuck or two of the others around here and have found they all work okay in my existing rotation too. In other words, this "sample pack" is what I have on hand in large quantities. And if a new razor turns out to be picky enough that it won't work with at least one of the blades I already have on hand, then I can't be bothered hunting desperately for the one obscure blade that it "maybe" will work with -- assuming there is any such beast.
