How do I tween Orientation smoothly with WeldConstraints?

So like I am making an RPG using a kit from Evercyan and tried to make a mob with custom attacks. When I used this code on a mob it just bugs out.

local humanoid = script.Parent.Enemy
local gui = script.Parent.Enemy:WaitForChild('WarningGui')

function tween()
	local tS = game:GetService("TweenService")
	local part = script.Parent.Sword
	local arm = script.Parent["Right Arm"]
	local tweenInfo = TweenInfo.new(0.45, Enum.EasingStyle.Linear, Enum.EasingDirection.In, 0, false)
	
	local properties = {
		Orientation = Vector3.new(-67.5, -90, -90)
	}
	
	local armProperties = {
		Orientation = Vector3.new(67.5, 90, 0)
	}
	
	local reverseProperties = {
		Orientation = Vector3.new(-90, -180, 0)
	}
	
	local reverseArmProperties = {
		Orientation = Vector3.new(90, 90, 0)
	}
	
	local createTween = tS:Create(part, tweenInfo, properties)
	local createArmTween = tS:Create(arm, tweenInfo, armProperties)
	createArmTween:Play()
	wait(1)
	local createReverseArmTween = tS:Create(arm, tweenInfo, reverseArmProperties)
	local createReverseTween = tS:Create(part, tweenInfo, reverseProperties)
	createReverseArmTween:Play()
end

while true do
	wait(4.5)
	repeat wait() until script.Parent.isFollowing.Value == true
	gui.Enabled = true
	wait(0.45)
	gui.Enabled = false
	tween()
	script.Parent.Sword.fireDamage.Disabled = false
	wait(0.6)
	script.Parent.Sword.fireDamage.Disabled = true
end