The Triumph can only be used in the most reclined *position* rearfacing--the other positions are all for forward facing. I'd use it for the baby rearfacing, b/c it's small and will fit well in an outboard position, esp if you install it at a more upright angle. I'd buy a new seat for your older dd, such as the Graco Nautilus, b/c it forward faces to 65 lbs and then switches to a high back booster AND later, a backless booster! It has really tall top harness slots, just a bit shorter than the Britax Regent (and taller than the SK Radian!). ($150)
Later, when your younger ds outgrows the older Triumph rearfacing (b/c it is outgrown rearfacing really early--like 12-18 mos b/c of it's short shell), or it expires (whichever comes first!), I'd replace it w/the newer Evenflo Triumph Advance, which fits well rearfacing in tight places, has really tall top harness slots (as tall as the Britax MA), and a rearfacing wt. limit of 35 lbs. It goes to 50 lbs forward facing, so chances are your younger dd will fit in it until she can go into a plain high back booster (she could then be switched into the older dd's Nautilus and older dd by then may only need a plain backless booster). Thei new Triumph runs about $130+.
Those are my thoughts.
hths
henrietta