The 6' post weighs approximately 5.3 lbs.
Yep. I used a post driver to install the ones I bought.
It weighs about a pound and a half. This post is studded as well.
No, I have only see it in green.
Yes. This 3 in. x 9 in. x 24 in. Metal Fence Post Driver is designed to make pounding these posts into the ground easier than other means. From my experience I would recommend that you use a heavy duty crowbar to create a pilot hole. This will help you to remove unexpected rocks that would make driving these posts into the ground very hard depending upon the size of the rock. You then use this driver to finish the installation.
The posts are made of mild steel, so you should be able to drill holes to match your sign.
The holes in the post are 1/4".
I have a couple of these in my garage and the 13/64" drill bit fits perfectly through the holes. If using it outdoors, you may need to use a washer with the nut and bolt to have a secure fit. Also, make sure you have stainless steel or galvanized screws that are rust-proof.
I can assume the holes will allow 1/4-20 hardware. I would pick up some 1/4- 20 bolts 1 or 1.5 inch long should work and grab some 1/4-20 nuts and washers as well.
I have never seen a 10 foot one in all my years.