I personally think that you are on the right track. But the question needs to be refined a bit better.

Ashigaru are also samurai, it's just that they are lower class samurai.

So in your question, I'm assuming that you are talking about a small fighting unit.

This website took the Tokugawa code and wrote out a chart of how many men a bannerman (hatamoto) or a lord (daimyo) is supposed to mobilize in case of war.

http://sito.ehoh.net/gunyakukitei.html

So according to the code set in 1649 a low ranking Tokugawa bannerman of 200 koku or 250 koku is supposed to bring to battle a minimum of 6 people. Himself and another 5 men, consisting of 1 samurai, 1 armor bearer, 1 spearman, 1 horse tender, and 1 porter. This seems to be the smallest fighting unit.

So this bannerman is riding a horse, has a samurai vassal in full armor (probably on foot), and a spearman vassal to aid them. This 3 man team is supposed to engage in combat. These 3 are supported by another 3 man team. An assistant to take care of the riding horse, an armor bearer to maintain the armor and weapons of the three, and a second horse (most likely a draft horse) with a porter (to carry the food, fodder, spare clothes, and other equipment).

In modern armies the logistics is a separate part of the army but in premodern Japan it was jumbled together. Since the smallest unit in modern armies is a fireteam of a NCO and 3 privates, this low ranking bannerman is the equivalent of a sergeant in the US army.

A lord (daimyo) of 10,000 koku is supposed to bring to battle a total of 235 people. Earlier in 1633 the code specified that these 235 people must include, 20 musketeers, 10 archers, 30 spearmen, 10 horsemen, and 3 bannermen. My guess is that a significant portion of these 235 people include porters to carry the food, fodder, and equipment necessary for war.

In modern armies a company has anywhere between 80 to 225 soldiers and is commanded by a captain or a major. So a low ranking daimyo of 10,000 koku is sort of like a captain or a major.

A daimyo of 100,000 koku is supposed to bring an army of at least 2155 men. But these were few. Only around 30 families controlled land worth more than 100,000 koku. The Maeda clan of Kaga domain was the largest daimyo (aside from the shogun) at 1.2 million koku and fielded an army of around 24,000 men towards the end of the Warring States period. By the end of the Edo period, most clans were under severe fiscal constraints and Kaga domain sent only 7,600 men to fight in the Boshin war of 1868-1869.