I have bought Time ROC ATAC pedals for with my Chrome Pro shoes, I'm currently in the process of buying proper cycling shoes for longer rides. Should I buy SPD shoes and ride with those or should buy SPD SL shoes and swap pedals for longer rides (once per week I'd think)?

Or can I buy SPD SL shoes and put my (SPD compatible) Time cleats on them until I can buy a second bike and have separate bikes for commuting and touring?