Hi Chris, and welcome to ATP. Both those Dahlias are in our Plant Database, (just click on Plant Database in the blue side bar to the left) although there aren't any pictures of Sarah Mae. From the description it is one that grows those huge 'dinner plate' size flowers so I would say the plant will be at least 3ft. tall, if not more.
Elvira has smaller flowers, around 3in. across at most, and the plant is also a more compact variety, maybe 2ft tall.
One more thing, Chris - you should probably take your e-mail address off that post above. (just hit "Edit" in the blue text at the bottom of your post) It could trigger a bunch of spam. ATP notifies you automatically when somebody replies to your posts here without us having to privately e-mail you and they don't give out your e-mail address (but you did . . ) .
