About to book a mileage run and wondered whether the hand baggage allowance if I am travelling in First and Business on KUP fares from SFO - LAX - MIA - CUN - MIA - LAS is greater than economy?

Dont want to check a bag due to tight connections, but is there any additional hand baggae allowance over and above what the aa.com site states for Economy? Ideally want my small wheelie trolley and a rucksack.

Metal is listed as being MD80 for one leg and 738's for the others. Not taken internal flights in US for years, but you used to be able to place your hand luggage bag (if it was large) by the steps at boarding and get it back as soon as you landed, rather than going to the baggage belt. Does that still exist?

Thanks

(Inexperienced AA flyer from London!)