I think I would only use 18" in very tight spaces and industries where a small switcher would be used or a Geep. Usually the smallest I use is 22"-24" and #6 turnouts in industries and short spurs. To me, anything smaller than the 2 are just too “toy like” to me. But that’s just my opinion, lol.
Got started on my modules today. Here are pics of the start of my project. Down at the bottom.
http://hometown.aol.com/ohiorailroader/layout.htm
$28.00, 2 hours and a vanilla Pepsi later, I have a module, lol. This is a straight section and I’ll add on a corner and maybe 2 other straights by the time it’s all said and done. A rough draft of the plan for this section will be up as soon as I’m done tweeking it. I’m pretty sure I have it all built to “spec”. Now I just need track, lol.