Hi scratchaker,
Unfortunately there is no way to know for certain whether one mattress will sleep warmer than another one relative to a specific person because there are too many variables involved that can affect sleeping temperature and there is no specific testing protocol that compares mattresses as a whole so your own personal experience is really the only way to know whether a mattress will be “temperature regulating enough” for you.
Having said that … post #2 here and the posts it links to has more information about all the variables that can affect temperature regulation (including the type of mattress protector and the sheets and bedding you use) that may be helpful.
There is also more information in post #7 here and post #11 here that compares the pros and cons of cotton to rayon and other viscose type of materials that may also be helpful.
I don’t think that either one of them would “sleep hot” for most people but only your own personal experience can tell you if you are the exception (which is part of the value of their trial period).
Phoenix