The first thing you need is a concept - some sort of idea as to what you want your spolas to look like (decorations, theme, etc.). Again, I urge you to peruse as many pottery images as you can to gain an idea as to what was most common during the period. I also stress attention to details in your planning - remember, the Greeks were very colorful and decorative with their armor, unlike Romans, which were more G.I. (uniform) in their appearance; there were lots of Romans that (armor-wise) looked exactly alike. Greeks were not fettered by this constraint, and dressed themselves according to individual taste.
HOW TO CONSTRUCT A PROPER SPOLAS
The spolas is a rather complex and somewhat tedious item to construct. I find myself needing to talk to myself out loud while constructing it, otherwise it would be easy to "paint myself into a corner."
RIGHT: This is the initial sketch for my latest spolas. Small changes here and there were to come, but the basic look was established at this point.
BELOW: This is a very basic pattern for a spolas.
Next you will need to make a pattern (out of heavy paper, thin foam stock or card stock). Notice there are two layers in the spolas. The inner layer has longer pteruges than does the outer layer - also they are staggered from one layer to the next (inner ~ outer). This can get tricky if you should lose concentration during construction. MEASURE EVERYTHING CAREFULLY AND REPEATEDLY!! Measure your chest, waist, front-to-back over the shoulders, distance between chest and waist and pteruges. The shoulder straps should just cover the pectoral area when tied down. The top of the tube section should just touch the clavicle area. Study the pattern here closely to get a basic idea of what needs to take place while constructing. Notice how the inner layer pteruges are shown to be overlapping toward the bottom due to the difference in length between the chest and waist diameters. This must happen unless you are shaped like a pickle barrel, and your chest and waist are the same diameter (see diagram). Note also how they are separate from the thorax area because of the "stagger" needed. Cut them in sections as you see diagramed. The outer pteruges can be of one piece with their respective sections although I haven't shown them as such (this saves sewing time!). Try to keep your pteruges no wider than 2" and no longer than the distance between your waist and your "junk." The outer pteruge rank is around an inch shorter than the inner. You should be able to see about a hand-breadth between the bottom tips of your pteruges and the hem of your chitoniskos. Do NOT wear your hem length long (I don't care how ugly your legs may be!) All Greek pottery shows a very short hem length. Proportion is EVERYTHING! You can make it perfectly, but if the proportions are off, it will not look right or fit correctly.
NOTE* The shape with the red asterisk on the diagram is an unnecessary piece - disregard it.