re: Ethnic food experiment

My experience is that raita is thin with more emphasis on the moist cucumber. Tzatziki is much thicker with an emphasis on the flavor of dense full-fat Greek yogurt...almost like cream cheese. For balancing the heat of spicy India food, I'd go with raita.

A less common way to enjoy spicy India is to drink salt lassi... a drink of water-diluted plain yogurt iced & whipped up with salt to taste and little cumin. Give it a few trys... it grows on you.