Probably best to let one of the more experienced Mums answer that one for you. Plunket did say to me that solids should be given whenever baby is still really hungry after a full breastfeed, so i would've thought that that means like 3 times a day if baby wants it - just not sure about with a 4mth old

Have you thought about topping him up with formula after your BFs or giving a little more formula if formula fed for those other two main day meals?