RomanArmyTalk

Hello to all
This is a general question that if possibly i would like the answer to....
Has anyone any info on
No1 A Republican scuta used in a Testudo?
No2 A Cearleon scuta used in a Testudo?
No3 A Dura scuta used in a testudo?
What are the ergonomics of the individuals or combinations of the above?
Obviously do not try to combine the Duras with the Republican etc etc....someone will try to.
Info recieved is greatly appreciated.
Kevin

I have no original sources, but a Republic (curved top) scutum and an Imperial rectangular scutum work ok together. Chances are, though this issue rarely came up.