Richard had three that I am aware of
1. As Count of Anjou-Maine on the red feild two gold lion rampant facing each other, the main shield he is portrayed with.
Richards 1195 great seal also has this image, along with coins issued.
2. A argent feild with a single red lion rampant facing left (dexter) as duke of Aquitaine, the earliest known seal of Richard.
3. The two gold lions passant over each other on a red feild, duc of Normandy seal
The three lions as we know them is only to be found on one seal in 1198, and on Westminster abbey, although that section was not built until 1250, during Henry's reign. it is thought that this is actually King Johns seal not Richards.
King John also seemed to of used two lions passant when his first seal was made when he was ten years old
King Johns seal when King
Heraldry is still in its infancy at this time, so whatever you choose will be fine.
I have two richards one has the ducal shield of Normandy, the other the count of Maine and Anjou as this is where he spent most of his life in Chinon before heading off on crusade.
My two cents