Basically, yes. Small batch brewing is great for what you're talking about experimenting with different ingredients, recipes, etc.

They guys at Basic Brewing Radio do it all the time, and h[ere's a pretty good article from BYO][1], but in general the proportions of the ingredients should be the same. So, if the small batch is 3 pounds 2-row, and 2 pounds wheat, the 5-gallon batch should have 60% 2-row and 40% wheat.


  [1]: http://www.byo.com/stories/article/indices/18-brewing-science/1410-small-scale-brewing