Nick, I used to ride a 47cm Absolutist and I just really didn't like the handling at the front end. Storcks seem to have some funny geometry up there. Most sizes are very long and low - long top tube, short head tube but the 47 actually has a taller heat tube than the 51. the head tube angles are fairly slack and the fork rakes very small (33mm as opposed to 43mm being more common) and for this reason I just couldn't get on with the handling. The larger sizes may be better with their steeper head tube angles, but the 47 really didn't work for me.
The quality of the frame was really something special - it had an excellent paint job that was very difficult to scratch. It was extremely stiff but not as harsh as you'd expect from all that rigidity. The scenareo may be more forgiving still. Of course component choice is also very important on that front.
I'd suggest you try to test ride on first to see what you make of the handling.
I've been riding a 2011 Absolutist for the last few months, same geometry & fork as all the others. I got a 63 cm, it fits me very well (I'm 195 cm).
I agree Storck sizing is a bit mad:- my 63 is sized like a Cervelo, shortish reach and big stack. Great for an old man like me. Smaller sizes seem much longer & lower.
I really like the handling, I can feel the fork rake difference, the steering is a bit slower than my other bikes so it feels really stable on fast downhills. A matter of personal preference I expect.
The build quality is astonishing, the paint finish is very nice and there are nice details like steel inserts around the drop-outs, and metal inserts around the brake holes. It looks built to last. The rear entry dropouts are a bit.... mad I guess. Markus Storck likes them, so I guess we all have to like them.
I liked my Absolutist so much, I bought another one. But this has quality issues which I am trying to resolve with Storck
. So, your mileage may vary!
If Storck can't get me a good Absolutist, I would buy a Scenero without hesitation, I bet it rides, handles and has the same build quality, just 150 grams heavier. A really nice bike.
When sizing the frame you need to take account of the fact that the fork is a bit longer than normal (10 mm IIRC. more madness?). Look at the stack & reach figures, not the head tube length.
But it's not like other bikes, so as CarpetFibre says you are either going to have to take a punt, or find a test ride. But you would have to pry my Absolutist out of my cold, dead hands.