When preaching, I generally control the sermon presentation using an iPad in landscape mode with notes displayed (in split screen as per below).
I note that the title of the next slide is previewed at the foot of the left-hand panel. However, it can be difficult navigating through long/complex presentations particularly should one wish to skip a slide or scroll back.
I would suggest, therefore, that the space designated 'Quick Screens' (as per screenshot below) is utilised to provide a preview of the previous/next slide. 
Blessings,
[:D]
