Suitable low power eyepieces for a F4 dobs

The rule of thumb with the likes of the paracorr is that if the scope is less then F5, you'll need it, if the scope is F5, you might need it for some eyepieces, if, its greater then F5 then chances are you wont need it, of course this is only a guide but I do think for widefield eyepieces you will need a corrector be it a Baader or Televue for your F4 scope.