Question ERF in Orbit G2 Toddler Seat?

I want to ERF my DD as long as possible, and we're now looking at getting her a convertible as she's about to outgrow her infant seat. It seems the longest ERF seats for most kids are the S4M, Foonf, and Radian RXT, and of those we like the Foonf best so figured, decision made. Then a friend was talking about the Orbit G2 Toddler seat so I went to look it up to see how it compares, and it appears to have no seated height limit, including no 1" rule. Is that accurate?? The shell height isn't that tall, but there is no seated height limit given for RF in the manual that I can see (looked at the online version), only an overall height limit for RF or FF and a note that ears cannot be above the top of the shell (which I thought was only the FF rule). 35 pounds isn't a very high weight limit, but since most kids outgrow height long before weight would this seat last RF for a good long while? Am I missing something? The seat appeals to me mainly because there are fewer chemicals, and the Foonf isn't perfect because it sits *so* high in my car, but the Foonf is a relatively green seat as well from what I understand (that has been coated in flame retardants, but hey) and if it RFs significantly longer I'd like to stick with it. Thanks in advance for any advice!

Here is a review I wrote of the Orbit Toddler: http://carseatblog.com/17163/orbit-toddler-car-seat-g2-review-you-spin-me-right-round-toddler/

I think I asked the rep about the 1-inch rule, but I seem not to have put it in the review, and I've now forgotten what the answer was. I, personally, would never use a US rear-facing seat with less than an inch above the head. I would definitely call Orbit. Other manufacturers have inadvertently left out information like that in the past.

As you can see from that post, my daughter had slightly more room in the Radian than in the Orbit, and the foonf is taller than the Radian, so the foonf will give you more room if you're leaving shell over the head.