If you can fit the
IC in there, you will be able to fit 2 Marathons. IMHO, I wouldn't worry about the
Roundabout. It will only harness to 40lbs and you want to keep your kiddos harnessed for as long as possible. You WANT to keep your kiddos
RFing for as long as possible and a LOT of kids will outgrow the RA in height before weight. The other nice thing is that you don't have to have that full 45 degree angle that
ic's are at. The can be between 30-45 degrees as long as the child has good head control and doesn't flop forward when they are sleeping.