That’s just, like, your opinion, man.

I think it’s perfectly sized. No need for change. And the OLED model is noticeably more lightweight than the original LCD model, so the newer one isn’t too heavy.

Yes, that’s normally a good rule to follow, since “whom” is for a sentence’s object, but this is a special case. The clause in question is either a salutation that has no subject or object, and so either “whoever” or “whomever” is correct, or it’s a subject clause (a noun phrase, really) with an unnecessary, stylized “to” for the sake of comedic impact, in which case “whoever” would be correct.

FYI, your post title should use “whoever”, not “whomever”.

A good trick to tell whether to use “who” or “whom” is to replace “whom” with “him” or “who” with “he”. It’ll be immediately obvious (to a native English speaker) which is correct.

Whomever invented LED bus advertisements becomes Him invented LED bus advertisements

Vs

Whoever invented some stupid shit becomes He invented some stupid shit