I wouldn’t recommend a 3 Core custom but if you have run 2 or 3 Core customs for a while and they work for you, then go for it. It’s a good combo where your sexual energy is transmuted to physical energy into exercise, physical shifting and martial arts.
Whether all the sexual energy is consumed by your physical activity depends on the strength of the physical activity and how much sexual energy you generate.
I can see that over time both your sexual energy and physical energy will increase as you keep improving your vitality with fitness and the development of your sexual energy.