I think expectations of what you want from your tank will also dictate how much time is needed. If you're super picky like me and are trying to create a show quality reef than it is going to require more time invested. In order to achieve the stable parameters most SPS require you will need time to interact with the tank daily. I think I spend at least 10 minutes a day just observing and feeding the tank. A lot is gleaned by looking at the tank and learning to discern what looks normal/healthy and what doesn't.
Routine water changes are the cornerstone of a successful reef tank. Are you going to have the time to do these, and the dedication to keep up on performing them? Will you have the budget to keep up with the salt, bulbs, RO filters, additional additives? This hobby can get expensive quickly. With SPS, beautiful colonies can take years of dedication to grow, but just a few days for all that hard work to be lost. The room for error is much smaller with an SPS dominant setup and the growth rate can be painfully slow.
If you're wanting to challenge yourself with SPS, transition yourself with a handful of frags and see how they do for the next 6 months. If they thrive and you continue seeing yourself enjoying the added effort then continue in that direction. If not, then it might be better to continue with a mixed reef.