Just booked a hot holiday in June, cannot wait

It will be 28+ degrees

However now freaking about the girls in the sun

Obviously I will put suncream on them (I have an organic one from the health food shop but am looking into the "safest" one I can lay my hands on)
How much sun can I let them be exposed to?? I am thinking we should try and avoid 11-4 times, right? But that may not be possible every day

And if I put them in long sleeves and trousers to cover their skin I'm worried about them getting too hot, but then is that the lesser of 2 evils compared with exposing their skin with suncream on?? DD2 won't keep a hat on either

Urgh wish I wasn't so worried about this, I really want to enjoy the holiday!!