Does one make a hatov vehametiv on two different kinds of grape juice? And is there a difference between for example example one made kiddush on the kedem light grape juice and then wants to drink red grape juice or two different companies of red grape juice?
One does not make the Tov Vehameitiv berachah on grape juice.
The reason for this is that the berachah was only enacted for wine, which has a special nature and influence.
Shut Or Le-Tzion, Vol. 2, Chap. 46, no. 13; Avnei Yashfei Vol. 1. no. 38, citing from ruling of Rav Elyashiv zt”l; Rivevos Efraim, Vol. 8, no. 599.