How much BOS troops did Elder Maxson bring with him from the Capital Wasteland?

How many soldiers did Elder Maxson bring to the Commonwealth? Was it a small portion of the total East BOS military? Was it like around half of the east BOS military? Was it the majority of the total east BOS military?

In my opinion, i'll say around half of its total military forces. Im thinking around 1,000 troops with 48 vertibirds in the initial invasion with more reinforcements coming in.