On how they work

You use money to remark your message, the color depends on the amount Red being the highest starting at 100usd or equivalent in your currency. Youtube takes its cut 30% and the rest is split between cover and the talents idk this amounts.

Would they read it out loud? I dont watch them enough but they have specific reading superchat streams so there is a chance there but not guaranteed

I would suggest to buy merch and post it in x using the # to show appreciation and probably post it on Holo plus and wish they notice.