Carrick

Hi all experienced potters , I have an Evenheat Rampmaster 11 kiln that has settings for a slow glaze 7 hours or a fast glaze 4 hours To date I’ve used the slow glaze on bisque fired to 04 using earthenware clay and glaze firing to cone 06; all turned out great .Can anyone tell me what the fast glaze does and can a four hour glaze work ?  

Cheers and thank you  Susie