On the contrary I think it does matter who starts for at least 2 reasons.
1. Whoever starts has to kickstart the offense and establish the flow. One of our guards is better at kickstarting the flow...the other excels in maintaining it while giving a different look.
2. Whoever starts goes against the other team's best and the relief man deals more with the scrubs. One of our guards is more capable (as you noted) on the defensive end and therefore would be al ogical choice to guard the opposing team's top pg while the other would be more free to focus on breaking down the weaker lineup for quick offence while the other team scambles in adjustment to the backup guards style.
I'll leave it up to you guys which one is which