You can always (and should) taste. In my case 5 minutes wasn't enough (Twining's Earl Grey) and it needed 6 to better profile the tea.
I tried it with Beefeater and Tanq 10 and also split base of the above (50/50 and 80/20) and in every blind test the Beefeater 100% was preferred (as it's quite taste neutral and the tea was better perceived).
I tried it with Beefeater and Tanq 10 and also split base of the above (50/50 and 80/20) and in every blind test the Beefeater 100% was preferred (as it's quite taste neutral and the tea was better perceived).