Use two fingers to put 4 pins in each space. I use my right and left index fingers. Then put the last two in the biggest remaining spaces. Easy.

Use two fingers two put down three quick pins in each gap. From there, you'll have plenty of room to put down the rest.

Do this ibn two phases:
1. Insert a new pin halfway between each existing pin, making sure that new pins are receding/extending in the same sequence as existing pins. (Hint: wait for existing pins to reach their apex, then put in a new one; insert each subsequent pin after a full rotation)

2. Wait for pins to fully extend. Once they've just started to recede, quality start putting in new pins one after another. If you've been careful in step 1, you'll easily have enough time and space to get all the remaining pins in.

You need to fit two new pins between each of the existing pins, which are continually moving in and out.

You've probably noticed that new pins can be inserted closer to existing pins if one is receding while the other is emerging, because the pin heads cross paths at a point further from the center. This is important, because there's not much room between the existing pins.

Rather than trying to eyeball the timing, try to develop a pattern that ensures all your new pins are alternating in/out with their neighbors. I start out putting one new pin in for each 3/4 revolution, until that is no longer possible.

Good luck! It is possible!