Yeah I was rocking these Under Armour Tech Shirts.
I also have the hip belt - never even though to use it. I also have the gut thing going on, and sweat a ton, so I appreciate the perspective from someone in a similar situation.
These t-shirts are great for yoga. They are light weight breathable and cheap, plus they look good in lots of colours(different ones are sold at different prices for some reason). I like shorts with a compression inner lining rather than full length trousers (like these ones). It's easy to get sucked into all the Yoga brands but I don't particularly rate them (lots of them are just standard fitness clothes but with a hippie pattern or logo and a higher price). Providing they don't restrict movement and preserve your modesty use whatever. https://www.amazon.co.uk/Under-Armour-Shortsleeve-T-shirt-Large/dp/B0073GO4YW/ref=sr_1_4?s=sports&ie=UTF8&qid=1490705186&sr=1-4&keywords=under+armour and https://www.amazon.co.uk/Under-Armour-Launch-Running-Shorts/dp/B00W41WSWG/ref=sr_1_fkmr0_2?s=sports&ie=UTF8&qid=1490705271&sr=1-2-fkmr0&keywords=under+armour+shorts+inner+lining