Forget clevers as they need to run shallow and the TRS drives run too deep.
You should be happy with 61mph as that is a respectable speed for that particular hull.
Your RPMs however seem a bit low with what you have presently so putty a larger prop on will only exacerbate the rpm problem and make it worst. The engines could run about 5100-5300rpm without problems but you only getting less than 5000 means that your pushing props too big for the boat right now.