POINT ONE: Do you want to be seen by the public as a Magician or a Mentalist? Or, are you just going to go with whatever is in current vogue, changing "specialties" as the next big trend comes into view? (which is what 90% of folks tend to do).
POINT TWO: What are your claims? If you are part of this "New School" mind-set that looks at it all as being "not'n but tricks" then it doesn't matter. On the other hand if you want to create solid mentalism that looks and feels real, that has your audience leaving the auditorium UNCERTAIN. . . well, why are you asking this dumb question, you already know what must be done, so accept that it's time to put the tricks on a shelf to play with here and there when hanging out "with the guys". . . the way the majority of the legends in Mentalism have done over the past century.
POINT THREE: There is what some jokingly refer to as the "Dunninger Solution" (though old Joe really didn't popularize the method, it was being used in the latter 1800s). You create a full-evening program in which the first 30-60 minutes is pure magic and the following (after intermission) is pure Mind or Spirit Oriented material. This was quite popular in the Victorian era in that resort guests could enjoy a Family Magic Show as part of an early evening meal; once the kiddies were tucked away for the night the Grown-up (mature audience 18 and up) would return for a more intellectually stimulating muse; everything from spiritualistic demonstrations to telepathy & hypnosis.
A related mode of separating the two was to have a guest/partner involved in the show that was "gifted" Willard the Wizard had his daughter Francis that could commune with spirits... (who would later team-up with Glen Falkenstein and become Mike Ammar's mother's in law...) There are several magicians that have taken this route as well as young wannabe mentalists that have teamed up with established act, creating a two-person feature such as the cabinet or popular telepathy type bits.
HERE'S THE PROBLEM: People come to see magic shows knowing that it's all tricks and silliness; it's an agreement between performer and audience and all is well. Mentalism on the other hand relies on belief by the laity in order to deliver optimum impact to the performer; the psychological nuances and foundations are in direct opposition to one another. The very instant you put too much magic into a Mentalism program or show off too much dexterity, the mentalism side of things will no longer have that investment of belief going for it, it will be seen as a trick... possibly a very realistic trick but a trick nonetheless. This is the same logic you'll find tied to the playing card argument. I'm not anti-playing card in mentalism though I strongly encourage people to find an alternative type of card to use while incorporating the same general effect & techniques; photos, post cards, etc. and where possible, using only an imaginary deck of cards.... get the people to VISUALIZE vs. touch and physically see the paste-boards.
UNDERSTAND... when I say that Mentalism must be believable I am not saying that you must take on the role of clairvoyant or seer; Kreskin is one of many that took a college professor type persona and made it work where Robert Nelson and many of his day choose to blatantly call themselves Mediums, Clairvoyant, Telepathists, etc. this was how it worked in those days and even Mr. Houdini understood such during the days he hosted guest mediums in his tours. But there is an curious logic to this mode of things (which the award winning Evansons still exploit) -- the fact that you are an ENTERTAINER working clubs, casinos, fairs, festivals and theaters should, for the average human being, more more than enough of a disclaimer -- evidence that you're probably cheating and yet, we're going to allow you the DIGNITY of deciding what you think rather than put words into your own mind; again, Mentalists depend on being able to solicit belief and an investment of belief (self) from their public.
Look at Hypnotism. . . if you don't CONvince folks to do what you want them to do, THEY WONT! You are psychologically, via voice, words and your own body language, leading them to believe that they are hypnotized... THAT'S IT! So why wouldn't you want to do this for the benefit of both, yourself and your audience?
YES, there are certain aspects of Mentalism that can be blended with magic, such as a Memory Act, the Human Calculator and obviously Hypnotism/Suggestion. I've used every one of these in School Shows to excite kids to learn because of how Math (one of my worse subject in school) can be Magical and empowering. . . same with memory cultivation and so forth. In other words, look at the genre, for lack of a better term -- the kind of mentalism type material you want to do IF you want to do both; find a way that allows the two (and yourself) the utmost advantage (psychologically) and "supports" both, one another as well as "the message" you want your audience to walk away with -- how they view you, what you do or, as in my previous suggestion, how the act can inspire them to take action in their lives.
Hope I've made some sense.