The only real context where it is appropriate to use the word "mostest" is straight away after the words "I like you the". "Bestest" is usually satisfactory in this context (and no other). Proofreading thoughts are off-matter unless a specific supply of worry from the text is Plainly determined. https://financefeeds.com/copyright-launches-100-million-fund-to-protect-users-from-hacks/