Whatever shape the scale armor is of the subject you're sculpting (say U shaped with a pointy bottom, like some Byzantine armor)), start at the bottom of the armor and work laterally...U after U, next to each other, one row at a time, going towards the top. From bottom to top, always.
The scale is not really a factor in my opinion...it's the same for any.
You could fashion a tool to get the shape...just make sure all ar the same size to start each scale.
You can insure this by rolling out your sculpting material flat, taking a straw or hollow rod the correct size, and punch out all the little discs to do each scale. They will all be the same size--so very important. If you have some scales of different size, they will stand out like crazy and the viewers eye will go immediately there.
Don't rush---there's no way to save time on this.