Hoping to get SMP on my crown also, booked in for May.
The crown & sides are the most common places to get SMP, there are several very convincing SMP videos on YouTube demonstrating how it gives the illusion of more density in the crown area. When it comes to getting more grafts done in the future, I'm sure some doctors will turn away anyone who has SMP as it makes the procedure more difficult for the surgeon. But many doctors still will do surgery after SMP, especially if you go to a trusted doctor.
Out of curiosity, can you share an image of your blended frontal SMP?