A great idea with some minor flaws.
Not to bury the lead. This is a wonderful idea, and well worth your effort if you have a Mars and dimensional accuracy is important to you. But please stick around and read the whole post.
A little background on the Mars.
At under $300 and with a wide community, this printer had me make the jump into resin printing. It's a wonderful little device but not without its quirks. Most quick reviews and videos about it seem to boil down to "Look, I made an almost acceptable D&D minature with this. Ain't it grand?!!!". Onee of the things I quickly found was that the Z-axis accuracy was not that good, particularly in the first couple of millimeters. As I want to use this for model railroad projects dimensional accuracy is a big issue for me. I found that there were discussions going on about this. A particularly useful one led by a Czech chap https://blog.honzamrazek.cz/2019/08/testing-the-precision-of-elegoo-mars-volume-3-new-view-on-the-z-axis-problem/ I tried a couple of his tricks and they didn't work, but at least I wasn't alone.A reply to one of hi posts led me to Mike's thing.
About this thing
I printed this with the main piece face down using the 14.3 bearing piece using elegoo black. I printed the screws using elegoo gray. A warning -- all the pieces were very tight. You may want to use Jan Mrazek's filter program to loosen them up a little. Also, if you have already been fiddling with the Z-axis, bring it back to stock. I had replaced the isolator block with a tPU block I printed. This raised the Z mechanism, and didn't leave room for the top screww without a lot of sanding. I intend to reprint this since I replaced the original block.The Main block is loose on the original top plate, which I was skeptical of, but it all seems to work.
The pictures of the sample rook, pretty much tell the story. As delivered (left) the drain hole is distinctly D-shaped from being compressed at the bottom. The groove near the bottom is also noticably lower. The little step wedges show that the small steps are quite uniform