i absolutely agree, this will be far easier with the motor out .
put it on the center stand,the exhaust comes off first, already got the carbs off, pull all the mounting bolts exept the rear lower bolt, have the boy help at this point . with one of you on either side pull that last bolt, the motor comes out the drivers right side.
what i've always done , is if you have a creeper (plank with wheels, for getting under a car) put that next to the bike , so when you pull the motor out you can just put it right on the creeper , roll it to the table or bench ... the 550 is a buck forty something, not sure how much the 350 engine weighs
good luck