Has anyone ever use a track loader/skid steer to drill piers?

Hi,

I'm in the process of looking for a mid-size rubber track excavator.
In the meantime, I do own a Gehl CTL70 and was wondering if I bought the right attachments; maybe I can do without an excavator and just drill my piers with the Gehl.

The piers are 18" in diameter and may need to go as deep as 20'.

If I go this route, I'm sure I'll need extensions of some sort.

Can anyone give me some ideas?
Or if you've done this before, I would appreciate anything you'd like to share.

Thanks