You have an obscure job in 1600's Brussels. You make reference sticks. You own a high-quality ruler (which are quite rare in that era) and use it to cut lengths of wood or metal to certain lengths and send them out the various craftsmen who use them as a reference when performing their craft. For example, the King requested that all rapiers for his army's lieutenants be of a certain length, so you created a set of metal rods that were sent to dozens of different blacksmiths and scabbard makers so those rapiers and their sheaths are made (nearly) identically.
Your father was quite wealthy and you inherited his 4-foot ruler when he died, while your older brother got all of his money. The markings on the ruler are at every ligne, which are 144 to a foot. However, firearms are becoming increasingly popular and you know that craftsmen want more accurate reference sticks these days.
You take a trip to the master ruler-maker in the city (the greatest in the world) and inquire about making a finer ruler. He said he could make you a new ruler with any number of divisions you like, so long as they are equally spaced and no closer together than .8 ligne. He also notes that you, being far poorer than your father, only have enough money to purchase a ruler up to 12 ligne long.
You are able to use your current ruler and this new ruler in tandem, however you can't justify this purchase if you only improve your accuracy from 1 ligne to .8 ligne. Is there a way to get a better accuracy? The optimal answer has the highest accuracy, not the simpler method.
A recent question about measuring ran into trouble with what was allowed in an answer, so I'll be explicit about what is allowed:
You may treat the two rulers as having perfect markings. You can compare two markings (or ends of an object) and declare that one is “to the left” or “to the right” of the other. You can perfectly align two markings (or ends of an object) if you choose to do so.
You are NOT a ruler-maker. If your solution involves transferring markings onto one the rulers or onto some other object, you cannot do this perfectly. Your transferred marking is no more accurate than your ability to measure it would be
You don't own an angle-measuring tool (at least not an accurate one)