I'm flying DEN-FRA-LHR next week in business. I glanced at the carry on luggage and it's very stingy--8 kg allowed only! Is this 8 kg per bag I assume? I have a backpack and a rollerboard that is 20" x 14" x 8" so it appears weight bay be my only issue. I really don't want to check in the 'roller as I want to get out of LHR as quick as possible not to mention the first time in 20 years I checked in luggage last month and LH lost it.

Where will the carry on baggage police kick in--DEN or FRA? Denver's flight shouldn't be an issue upstairs on the 744--plenty of room. It's a 320 over the Channel to LHR. Are those bins designed to take my rollerboard in longways?

What's worst case? I have to gate check it? Will I wait in the jetway like I would for a gate checked UA flight or it's checked to baggage claim?

Thanks in advance.