From the top of the sled to the bottom of the stainless arm, its 3 3/16". I tried to match the height I found worked well with my original sled. I used 4 layers of 3/4" plywood that I cut at the same time as the new sled. I had figured out the location of the pantograph arms in Fusion and wanted to just through-bolt the pantograph in place.
I didn’t even notice that. It was pretty late last night when I got this all assembled. I’ll have to check if that’s because of the twist. The right master link I used came from the Maslow kit, the left came from your hardware kit. I think they are slightly different, and that could be part of the problem. There may be a second master link that came with the original kit, I’ll have to do some digging in the mess that is my shop. Worst case, I can either sand down the face or widen the hole a little to get the clearances closer to what I need.
I had positioned my weights to get the center of gravity as close to the bit as possible. Is this necessary? I can shift them back down to where I had them on the original sled.
On my machine, this will probably be exaggerated a bit. The only space I have for the machine presently is in my shop trailer, and there’s only about 112" where it will fit. I had to make a smaller frame as a consequence, and I figure I probably lost about a foot or two of usable machining area.
I used the 1/4"-20 bolts and nylocks that came with the kit for connecting all the linkages. I did add 2 Oilite thrust bearings between the linkages to reduce friction between the joints. Not sure how necessary it is, but I figured it couldn’t hurt. I also cut down the bolts to reduce the amount of thread that was sticking out.
To connect the pantograph to the sled, I used 1/4"-20 x 5" carriage bolts, which I will admit was a HUGE mistake. I will be switching them out for regular hex cap bolts when I get the chance. The carriage bolt did not hold as well as I was hoping in the plywood while I was tightening the nylock, and it just spun. I ended up grinding a slot in the bolt head with a cut-off wheel, which allowed me to use a flat head screw driver to tighten down the nuts. I again used Oilite bearings between the plywood and the linkages, as well as between the linkages (I’ll post more pictures tonight when I get home). I used quite a few of them to get the height of the arms the same. Probably not entirely necessary, but I am a perfectionist, hence the username 
Yes, mine rattled quite a bit. I tried my best not to shake it like a 12 year old checking to see if his birthday gift is a new LEGO kit, but I only have so much self control. The box was packed inside a plastic bag, and as soon as I took it out some washers fell out. I’d imagine if you’re missing anything, it’s probably a couple of washers. Based on your other posts, I’d imagine you have some 1/4" washers floating around the Empire of Dirt. 