How can I scale and position buttons depending on the canvas size of a ScrollingFrame?

So I have an inventory GUI. When items are added the canvas size of the scrolling frame increases. Unforunately, when this happens it affects the size and position of the buttons.

I just need to know how I'd calculate the size and the position of the button so it looks like the same size and is spaced out the same no matter what the size of the canvas is.

This is what I've tried. I can't get the math right.

local getInventory = player.Inventory:GetChildren()
for i,Item in pairs(getInventory) do
	if Item.ClassName == "IntValue" then

		local button = Instance.new("TextButton",GUI.Inventory.InventoryList)
		button.Size = UDim2.new(0.925,0 (0.055/GUI.Inventory.InventoryList.CanvasSize.Y.Scale),0)
		button.Position = UDim2.new(0.025,0,(PositionUI + 0.015),0)
		PositionUI = PositionUI + 0.065/GUI.Inventory.InventoryList.CanvasSize.Y.Scale

	end
end	
PositionUI = 0