Can you choose just one SE razor?

Same as Loedse. I used the same make of blade too. I was concerned about it being a bit more aggressive (more blade exposed; sorta open comb etc.). I needn't have worried: gave me a bbs after 2 passes and judicious use of 'the fat'. Quite mild and forgiving. Billy and others have testified that the US 1912 patents lack the aggressiveness of the English ones.
 
OneBlade is my favorite SE of all time now. I've tried al of the Artist Club style razors except for the ATT SE1 and I think I'm done with those. I just highly prefer the traditional GEM blades. So a GEM in the OneBlade for me, but if I'm going vintage if have to say Clog Pruf or ER1914.
 
Unfortunately, my answer won't help you at all. My one SE razor choice would be a G.E. Jones shake sharp, and that would be because it not only shaves well, it also takes DE blades, giving me many more choices than the standard GEM, injector or Kai/Feather options.