-
@punkture With the KG381 series, even for the 49cm they have a 53.9cm top tube. You'll also go down a further 3cm on the head tube length, which will make for quite an aggressive ride. This is a [bad]photo of my GF on the 52cm I had (she had a 49cm, we had matching bikes :-) ) but you can see the drop.
For her bike, you can see how short the head tube is on the photo below. I think if you've got stiff shoulders, you might need something with a bit more stack, as when I tried her bike, the seatpost was at the maximum.
Mine are both 53s so just a touch too big as the top tubes are 55 and I need 52.5. Have you sold yours (though I think it may still be too big)?