Maybe I can, but I am failing to grasp how templates or the modules work, we have these resources where only the ami is different (and sometimes the count):

    resource "aws_instance" "nomadclients_tick" {
      ami = "${data.aws_ami.nomadclient_tick.image_id}"
      instance_type = "t2.micro"

      count = 3

      iam_instance_profile   = "${aws_iam_instance_profile.consul-join.name}"
      subnet_id              = "${element(aws_subnet.consul.*.id, count.index)}"

      vpc_security_group_ids = [
        "${aws_security_group.rule01.id}",
        "${aws_security_group.rule02.id}",
        "${aws_security_group.rule03.id}",
        "${aws_security_group.rule04.id}",
      ]
    }

    resource "aws_instance" "nomadclients_tock" {
      ami = "${data.aws_ami.nomadclient_tock.image_id}"
      instance_type = "t2.micro"

      count = 3

      iam_instance_profile   = "${aws_iam_instance_profile.consul-join.name}"
      subnet_id              = "${element(aws_subnet.consul.*.id, count.index)}"

      vpc_security_group_ids = [
        "${aws_security_group.rule01.id}",
        "${aws_security_group.rule02.id}",
        "${aws_security_group.rule03.id}",
        "${aws_security_group.rule04.id}",
      ]
    }

The examples I have found feels very difficult.