Narrow Gauge tie dimensions & spacing *PIC*

I'm rebuilding the Sumac & Northern, my Dad's live steam railroad (1/3 scale, 12" gauge) and want to use ties that are as close to scale as possible. Power is a pair of Shays and two 4-4-0's.
What is the length, width and height of ties used on various 3 foot gauge railroads, such as the D&RGW, RGS, EBT, White Pass, Tweetsie, Westside Lumber Co. and others? Also what was the normal tie spacing on these lines?
We are using 12lb. and 16lb. rail, so we can get away with wider than scale tie spacing, but I'd like to keep the look of a typical narrow gauge line.
Thanks for the help.
Michael Allen