I do one cylinder at a time also and I have been wrenching for quite a few years. You may need to do the multiple adjust method if you have four or five valve jobs at once or if your slappin together an engine on jeff gordons car so he doent get lapped
but otherwise the couple extra minutes to do it right and one at a time is well worth not having to redo the adjustment.
I have allways said get good and then work on the fast part.
Its is also easier to keep track of if you have to stop for a phone call or to grease the door handle on your neighboring technicians car when he isnt looking.