Using a template is ideal, doesn't matter which straps you are making as the connections will always be the same at the end. I went with ABS plates for the first few builds but they are some extra work when having to heat to conform to areas that are curved, so I quickly converted to nylon, quicker to make and contours to the armor a lot better in places, can just use a solder iron to make the holes and it also seals around them. I have a container of ABS strips I use, some are curved and I use them to hold down the nylon while gluing, then just add magnets or clamps.
Coming along nicely.