Stage is between the As. A and B usually gets used for the seats up close divided between left and right side. C is on the floor behind A&B. D where my 1st seat was has an ok view of the stage but you'll need to look at the big screens alot, if the catwalk is extended out front D's view is great for that. E I think may have been on the floor too, the best place to check for a current seating chart where those letters will be more accurate is here
http://www.yokohamaticket.co.jp/ and use google chrome to translate to english makes it very easy to navigate without reading kanji.