Thanks a bunch for the link to the images, that's really helpful!
Candled tonight, as it is day 14 now, and I'm pretty positive the one I thought was a dud on the first candling is indeed a dud, but I can't quite throw it out yet. I have a second egg that I'm not sure about, at the first candling I was pretty confident I saw vessels, but it definitely doesn't look as far along as the remaining eggs. The other 15 are very dark, lots of thick vessels visible, and on many of them, I saw movement which is SOOOO exciting!!!!

For now I'm leaving the two questionable ones in there... what are the chances they will explode if no good? I've heard horror stories about that, but don't know how it really happens, as I've never had an egg explode under a hen... Did have one left in a nest after hatching, and when I went to crack the duds open and explore what was in them, the one egg did sort of pop when I tapped it to break the shell, a bit explosive, but I don't think it would have done that without me trying to crack it open... is there any harm in leaving these two questionable ones in there? I figure if I get to day 18 with them and all the other eggs are pretty much dark and these still look like they just have a dark spot floating around, I'll leave them out... advice?
Also found it interesting the range of weight loss on the eggs. Lowest was around 6.25% and highest was 18.75%!!! Holy cow that's a range... seems a bit steady as far as which eggs are on the low end and the same egg had the record high. Average overall is 10.34% which I guess is pretty good for 2/3 of the way done? Humidity is still reading around 45% on one meter and 55% on the other, and I'm still just keeping the one trough filled... guess I'm going to wait another 4 days!!!
On a separate note, my two broodies are still chugging along... Checked on them today and saw an egg peeking out from under one of them... thought "oh no, I've given her too many eggs" and went to take the visible egg and donate it to the other hen, who has fewer eggs under her. When I retrieved it, I saw that it was a full size brown egg... I didn't set any full sized brown eggs under them!!! I have one hen in my layer flock who gets out of our netting every morning and goes back in for bedtime, spends the whole day out being naughty by herself. She had been coming into the silkie's coop which is also open during the day, and laying her egg in one of the nesting boxes. So, I guess she liked the crates I have the silkies in better... picked up one hen to check her eggs out, and sure enough, a second big brown egg. Picked up the second hen to check and a THIRD daggone egg. So the one little hen had TWO extraneous big eggs under her, and I am just hoping and praying that the second one was laid today and the important eggs didn't get overly chilled with the crowding... The other hen I'm not so worried about, but the eggs under her are not as important!!! Great, another thing to stress out over... lol Guess I'll have to check under them every day now to be sure... they're gonna love that. I would just leave the coop closed, but the rooster likes to get out during the day, and I see the hens out every now and then stretching their legs and scratching for bugs, so I hate to leave them closed up but still...