I am a reasonable cook, but I can never quite get Indian food 'right' in the same way restaurants can. Edible and even decent, yes, but spot on, no. I think in part because I don't cook with enough ghee or cream compared to restaurants.
I often order extra take out to turn into lunches. I have no idea what a half tray would be in terms of servings, I would think that depends on the restaurant. I would personally opt for off the bone if you are ordering it, as a) you'll get more meat in the tray and b) no bone meat reheats better from frozen IME.
One way to stretch the meal slightly is to add some vegetables (not to mention it is healthier for you too!) I find some red peppers, peas and/or onions go well with a tikka masala sauce.