It seems to me that rather than alternating dark and light steps, it would be better to have, as heric said, a light stripe on the edge of each step.

I presume that, in the renovation, if your church is not already wheelchair accessible, that provisions for this are being seriously considered. I recall a synod conference some years ago where I attended a workshop on making churches accessible to the disabled. One pastor commented that his church didn't have that problem. There were no disabled folks in his congregation. It had never occurred to him question why that might be. I quoted the line from the movie, "Field of Dreams" to him:   "Build it, and they will come." He looked a bit bewildered for about ten seconds while he contemplated that, then a very visible, cartoon-style light bulb appeared over his head. I think I may have scored a point.

Don Firth