I take it your borrowing gloves at the moment yes? Well when you next go to muay thai try on the different sizes of gloves until you've found a pair you're comfortable in,and then ask someone if they're 14 oz or 16 oz. The sizes on the internet don't vary too much from each other, I recommend you buy your first pair cheap until you've worked out that A) you want to continue muay thai and B) That's definitely your size.

I'm trying to get some twins training gloves for some sparring and bag work but I'm a little puzzled as to how I'm really going to know which size to get since I'm new to Muay Thai and don't know whether I should get 14 oz or 16 oz especially since I obviously can't wrap my hands up and try them out for myself. I really don't want to order them wait for a week only to find out they don't fit and have to call them back. I would go to a sports store and pick some up but all the sports stores near me only sell everlast gear which I hear never lasts (ironically) and is not very good quality. Im wondering if size and weight have anything to do with it also I'm 5'6 male and weigh 168 pounds if it does matter