I use a dedicated hand trolley for my 10" Skywatcher. I think i paid about $30 from Repco. I went to clark rubber, bought some strips of foam and fixed it to the trolley all over the place so as to not scratch the scope. I do not strap the scope to the trolley as the Skywatcher comes with 2 big knobs/handles to raise and lower the trusses of the dob. If you look at this picture you can kind of see the knobs. They're just below and to the left of the focuser:
http://i421.photobucket.com/albums/p...Trolley001.jpg
To tip the trolley back/up to move the scope, on both sides I put my forefingers on the little knobs and ease the scope back so it's flush against the trolley then put my thumbs behind the side rail of the trolley and pull the whole lot back. Once it's back and sittng on it's wheels in a balanced position, i put one hand on the top rail to control the trolley and keep one hand on the knob/side rail to keep the scope flush against the trolley. Using this method i go up and down my stair no problems and the scope 'falls into' the trolley and stays there.
I would suggest that you keep the tyres pumped up a little bit but not firm, this takes some shock out of the trolley. If they are pumped up firm the trolley will bounce and shock the scope to no end... and you'll HAVE to collimate
The quality of the Skywatcher black diamond dobs is superb. I would even go as far to say they're a premium scope.
cheers