Wing tip wheels, one or several?

Our self-launch glider has downturned wing tips. From the factory, there was nothing more than a skid to make contact with the ground. Over time, people seem to have settled on putting a roller-blade wheel there, presumably because it dramatically improves ground handling. However, the wheel isn't very pretty and because of the drooped tips there's no way to install the wheel without it dramatically disturbing airflow.

I'm wondering if two small inline wheels could suffice to replace the one big one. In my mind, the advantage of a bigger wheel is reduced rolling resistance on uneven ground. However, inline wheels might close that efficiency gap, without having as large an effect on airflow.

Thoughts?