I have tried several configurations and have come up with this as the best.
I removed rear seats and seat-belts. Replaced belts with hardened eye-bolts. Then ran a caribeaner through eye-bolt.
Using the L.A.T.C.H. system I locked the outside directly to the eye-bolt and ran the inside through the caribeaner over to the other eye-bolt. Took the top mounted strap and attached it to the eye-bolt as well. It took a lot of pulling and sitting and jamming my knee into and out of but it finally paid off.
The seats used are COSCO Touriva
I purchased them at K-Mart for $49 each.
They are good for 5lb-40lb (2.3kg-18kg)
19"-40"(48cm-102cm)
My children ar 12mo. and 3yrs.
I hope this helps any Dads or Moms
This was a factor for purchase in our house.