In computing a little byte doesn't make a difference at all and http vs https performance is not something inherent to the specific protocol, there are a lot of things that can mix up to give you better/worse results using https or not like how busy is the ssl port and things like that.
What I mean is that this kind of optimization is useless at this time because it can be barely measured and if you can go with https go with https is better for the end user.