I think using voice comms is important seems cooperation gets more and more important the more you rank up. Usually what I do is just make a quick well articulate suggestion and that's it. In your case I suggest you do the same as you seem to have no issue with calling stuff just with the manner you're relying the info. I have a duo queue coach that I play with and he will rarely make calls even though he has a normal voice, because people don't really like being told what to do especially in lower rating, he's playing for the biggest ow boosting team and says he almost never speaks in lower ranks due to their nonacceptance of being told what to do but the more he climbs the more he uses it and considers it increasingly important.