If you buy a 10", I don't think you will be wondering evertime you use the scope if the 8" would have been that much lighter (they are both big scopes) BUT I'm sure everytime you're looking at a faint fuzzie, you'll be wondering how it would look thru a 10"
Incidentally, Bunnings have a great flatbed hand trolley for $40 which works a treat for my 10" collapsible