3 across in jeep liberty

Hi all, I'm hoping someone can offer me some advice. I have a 2007 Jeep Liberty, two DS's and expecting my 3rd in August. DS1 is 4 (4yr5mo when baby comes) he is 39 pounds and 44 inches tall. His torso height is 16 inches. he currently rides in an Evenflo Chase, harnessed. But he needs a new seat since he is one pound shy of the harness weight.
DS2 is 1.5 and he is 27 pounds and 33 inches. He currently rides in a Fisher price safe voyage.
I have a Graco Snugride for the baby.
I need to figure out how to fit them all. I have a few other seats to use also, and am not opposed at all to purchasing new seats.
I also have a Cosco Touriva, Evenflo infant seat I could use, and I bought a Graco Nautilus in hopes that it would work(i couldn't get it to fit)
I think I have to buy a Radian.
I don't really have any preference as to who sits where, I just can't have a RF seat behind the driver, since my DH Is tall and the liberty is cramped anyway! I do NOT want my 4 yr old to be in a booster, I want him harnessed for at LEAST 2 more years.
So anyone have some advice? I hope this makes some sense, sorry it's so long!
TIA
Miranda

I think a Radian or two would be key to getting 3 across in the Jeep, although I haven't personally done a 3 across installation in a Liberty. This previous Liberty thread, and particularly Skipspin's post within the thread, has some seat suggestions for 3 across in the Liberty: http://www.car-seat.org/showthread.php?t=15356 Congrats in advance on the new baby.

Thank you for your response. I will probably order 2 radians tonight. I just don't like the feeling of ordering something I haven't seen or tried the kids in but I guess it's what I have to do. I do have another question though, I bought a GN yesterday, and I mentioned I couldn't fit that with the other ones, but when I did have my 4 yo sit in it, he was at the highest harness slots. Does the Radian have higher harness slots than the Nautilus?
thank you for your help
Miranda

The Nautilus' top shoulder harness slots are approx. 18.5" tall, a bit taller than the Radian's based on specs and comparisons posted to the board. The Radian is unique in that its manual also allows the child to continue to use it until the tops of the ears are even with the top of the Radian's shell once the shoulders are above the top harness slots. It's somewhat controversial among the tech community in terms of concerns about spinal compression, but the engineer who designed the Radian recently assured us during an online chat here that it's allowable and safe. It might also pose a comfort issue for a broad shouldered or taller kiddo to use the Radian with shoulders above the top slots.