Perhaps you could wait until they are about a centimetre or two in diameter. Use a tweezer to slowly take out the seedling with the soil while trying your best to keep the roots intact. Most of the droseras are hardy and can survive a little jostling, but you might want to remove the bigger ones first. Small ones get shocked very easily.
Btw, when you repot the young seedlings, be sure to keep them away from winds. I had a situation where my 1cm diameter droseras were blown away by the wind after I repotted them!
They are quite light after all