I compared a Safeseat to two Snugrides at BRU, and found that the release button on the two Snugrides was farther down the back of the carseat. SInce I had the front passenger seat back to the point of touching the car seat, that low release button actually made it HARDER to un-do the Snugride. I think it took up less room, but the point was moot for me because of the location of the release button.
Some of the Safeseats have a big red recline dial on the front, and the seat seems like it takes even more room the more reclined it is. Double check that the seat is not reclined at all, although I suspect it wasn't in the first place.
I have a 2004 Baby Trend Latch Loc car seat and it's a bit smaller than the two Gracos (but you're supposed to put the handle down when driving, which then eats up that extra space.) It also has a release button in the front of the seat (by baby's feet if they are rear-facing), so you don't have to force your hand between the carseat and front passenger/driver sheet.
We had a 1993 MAzda Protege when DD1 was born, not a big car at all, and the front passenger was always a bit uncomfortably far forward the whole time DD1 was rear-facing. But it wasn't a disaster either. It's probably harder with twins, since the driver gets affected too. I hope you find a solution!
Advice and commentary on living overseas
DD1 15, DD2 12, and DS 9