Zippy owners... does your baby slouch too, or is it just my DS?

[silversun]

I love my 2004 Zippy, but I'm not sure my 11-month-old DS feels the same way. He seems happy enough, but he sure doesn't look comfortable. It's as if the seat is too deep for him (or the part of the harness that goes between his legs is too far forward) and he ends up slumped down in the seat after just a short while. Is it just that the Zippy isn't a good fit for him? Or is this a problem for everyone with a Zippy? Or a problem for everyone with an 11 month old?

I want him to be as comfortable as possible in the stroller (for him and for selfish reasons - errands sure would be easier if he could stay happy longer!), so I'm wondering if should try putting a pillow behind him, or maybe just look into a new stroller altogether. Recommendations of either sort would be very welcome!!

Thanks!