Yep that's right. Keep him rear-facing until he hits that first line, then he needs to turn forward-facing. The higher line is when he needs a new seat as he's outgrown that one. Lots of people get 2 years plus rear-facing in that seat. The first batches that were released with height markers actually came out with incorrect seat covers, on these covers the height markers were too low. If you want to check if yours is one, just look at the model number and date of manufacture on the seat and give SnS a call. They'll be able to tell you if you have the old cover or not. If you do they will send you the new one with higher markers for free

Also don't forget whichever cover you have, if you remove the infant insert, it will give you even longer rear-facing

It also does not matter if his feet are touching the back seat it's completely safe. There have never been any documented cases of leg injuries of rear-facing children in accidents. The opposite is true, there are many recorded cases of leg injuries in forward-facing children. They are rarely uncomfortable rear-facing either, they fold, cross or hang their legs over the sides of the seat, even stretch them out up on the back seat and a re very comfy. They are just a couple of things you'll hear people say who don't know the benefits of rear-facing.