I find using longer sections of track in the center of the grade allows you more flexibility where you place your supports. Using shorter pieces at the grade transitions can make it easier to fit in a smaller space. As noted above, test with temporary setups and use your longest engine and rolling stock. Also test with any rolling stock that has lower clearances like heavy duty depressed flat cars, Schnabel cars, or similar. My last test is always a longer consist to see if any cars bind or come uncoupled (different mfgs. can have slight variances on coupler height). Yes, I have had 2/3 of my consist suddenly roll back down the grade with neither coupler open.
Good luck!
