I know you don't have the size in KB at your fingertips. But you're probably thinking, “Smallish... tiny bit of CSS, forms JS, optimized images. Definitely smaller than our corporate home page, I can tell you that much.”
What if I told you that your Marketo LPs may be forcing users to download your home page's full HTML, twice— in addition to downloading the LP and its own assets?
(And I do mean “your home page.” Not something the size of your home page, but your actual home page.)