Blazon questions
In drafting out a COA I'm finding myself somewhat befuddled with the heraldic language of the blazon.
Here's what I've got so far:

Coat of Arms: Gules, a fess embattled or, between in chief three escutcheons, and in base a harp.
Crest: A dexter arm embowed vested azure, the hand in a buckskin gauntlet proper, grasping a cavalry saber argent, hilted or.
Motto: Riamh Nar Dhruid O Spairn Lann (I will likely need to adjust the scroll to have that fit)
Do I need to specify the color of the escutcheons and harp and the orientation (fesswise?) of the escutcheons? Do the helm and the mantling need to be described?
I would sincerely appreciate the opinions and advice of our heraldic scholars.
Mike Nugent
Riamh Nar Dhruid O Spairn Lann