23 or 25 may be 27 ???

Hello



there this is the first time I wrote about the forum ...





I own a class b + 28 feet and I want to sell to buy an airstream



I like the floor plan of 27 feet but too big Im stess to drive with a 27 feet !!!!



I never tow a trailer befor so dont know anything about that !!!



We want to buy a use one !!



my questions



is it easier to drive with a 23 or 25 or 27 feet?



or feeling will be the same ?





Gasoline is much more expensive to drive with 27 feet? or realy cheaper with a 23 feet ?



What I must have hitch on my car to tow safe and comfortable ???





I want to buy a Mercedes ML350 2010 with a capacity of 7200 pounds





Thank you so mutch for all your answer !!!!