I have a template letter on this topic and addresses to contact the SCOTUS justices and clerks. Please private mail me if you’re interested.
I’m not sure a template letter is the way to go on this.
Yes, include the necessary information but it’s important to vary the letters so they aren’t just carbon copies.
Handwritten letters really stand out, in contrast with mass produced printed ones. Straight, to the point, original letters have an impact.