I can't speak to the dosage, but I will say when we were increasing my DD's iron we used floradix, cooked in a cast iron pan, and gave her iron rich foods.
This has worked great for us. I was supposed to give LO Poly-vi-sol (for the iron) because he was a preemie, but instead, I did what LalaMama81 does, and I've also been giving him cod liver oil daily since we brought him home (cod liver oil isn't iron-rich itself, but it helps babies absorb iron much better). I have also given him liver that I mash for him (only a few times), and I've made sure he's developed a taste for iron-rich foods like spinach (which he now loves).
It's all paid off... at his 9-month appointment today, his hemoglobin was 13.9... his ped was super-pleased with that so I didn't have to confess that I refused to give him Poly-vi-sol!