The only bit of advice that I can give is to check with the suppliers where the building is manufactured. Got one delivered last year in kit form ready to slot together (quick job), but teo of the timbers were split/broken, and since the building was manufactured in Lithuania, there was a 5 week delay in the replacements arriving, which meant that the rest of the timbers (and there were a lot of them) had to be left protected the best it could in the garden and taking over the garage.
Not a joyous experience!