Woops! That was for a different heraldry my bad. How's this: Argent, a rampant hart proper, on a chief vert, three crosses formée, argent.
You have laid out the blazon very well.
If I might suggest:
“Argent, a hart rampant proper, on a chief vert three crosses formée argent”
Take, for example, the very similar blazon of Henry Russell (c. 1455):
“Argent, a lyon rampant gules, on a chief sable three escallops of the first.”
The phrase “of the first” meaning the escallops are argent.