Lincoln took almost five days. That may seem like a long time , I don't know. I have nothing to compare it to with other carvers. The photo does not show the true depth, believe me, it is deep! The hardest part for me was to engrave in the deep areas without scratching up the pillars. I used a bridge quite a bit for the gravers as well as burs with a rotary tool.
I inserted another photo with the other two at the beginning of the thread. It shows a bridge and how I use it. It is basically a ring ( sometimes with a handle ) with grooves in it to support and slide the graver in. It acts like a fulcrum, and is really good for steep angles. I did not use this with the rotary tool, sorry I wasn't specific.