Yep - we used the rollon stuff for babies in the Cook Islands.

Alot of sunsceens have a chemical called PABA in it - which is really harsh on my face, I peel because of it. Alot of people react to it. I have to use a special cream for my face, and use a different one for my body.
I would aim to find a special baby one, but as for the only about 6 months thing - well I say better to have sunscreen on than not IYKWIM??

HTH
Fi