It looks good. I am wishing you the best of luck. Just read everything you can on BYC and on other sites. There is SOOO much information out there it can be overwhelming, at least for me.
This is probably my new favorite link. If you pay close attention to the humidity at lockdown, and ventilation during the entire hatch I think you will have a good chance of getting those precious eggs to hatch.
http://msucares.com/poultry/reproductions/poultry_pipped.html
To answer some of your questions... and I am no expert, but this is what worked for me.
1) how to I callibrate the thermometer/hygrometer?
http://exoticpets.about.com/od/herpresources/ss/hygrometer.htm
I had 3 thermometers in mine, talk about nervous. One thing I have that I used at night is a thermometer that is designed to be used in a barbecue, so it has a remote. I would put the probe in the incubator at night and then take the remote part to my nightstand at night and set is so an alarm would go off if it went over 102. I only had it happen once.
2) Is the temperature supposed to be 99.5 F. and humidity of 50% ?
That is the correct temp. I ended up putting a second fan in mine at about day 7. I didn't like the warm spots so I put one fan down low and one on the opposite end of the incubator at the top. I ran my humidity lower, about 35% the first 16 days
3) When do I raise the humidity?
Typically day 18. I started raising mine higher on day 16 as I wanted to make sure that I could get it high enough and keep it there before lockdown. I am glad I did that as I had to add a bigger tray of water to get it to stay up. I also ran tubing through my vent holes into my water trays so I could fill it during lockdown without opening the incubator. I used a syringe to add water through the tubing. Also, I had eggs pip on day 19 so I am glad I was ready. I ran my humidity around 65-75 during lockdown.
4) I'd like to make an egg turner. At what angle should the eggs be tipped in the tuner? Is it as much as possible without them falling out, or less?
My turner looks alot like yours and I just turned it side to side, probably 45 degrees or so. On about day 10 I got nervous and started raising the end of the incubator about an inch, as well as using the turner. I could only turn 2x daily during the week, but I would do 5x on the weekends.
I just did my first hatch in my homemade incubator and got 9 out of 10 and I think the 10th was an early quitter. So it can be done. Maybe it was begineers luck. I hope not 'cause I want to do it again. I'm hooked.
Other tips from a newbie.
I took my eggs out of the carton for hatching, I won't do that again. I did not like the hatched chicks playing soccer with the unhatched eggs.
Next time they will hatch in the cartons.
I had 3 vents in my incubator. One on each end, at different heights, and one in the back.
I only candled once, at about day 10. I thought that the less the eggs were handled the better. I left them all in as I had no idea what a clear egg really looked like. Now I do. I candled again at about day 23, and then cracked them open. They had never developed.
Once they pip, you won't get any sleep.
A watched egg never pips, and a watched pip never zips
If I needed to open the incubator, and I did to put the eggs back in cartons, I misted the inside of the incubator with warm water as I did it. Not trying to get it on the eggs, aimed for the lid, but some did fall on the eggs, obviously. Maybe not a good idea, it worked for me and I would do it again if need be.
When adding water, add warm water. It makes a difference in temps, especially during lockdown.
If you have your incubator in an area with fairly stable temps you will have an easier time getting the temps and humidity stable.
If you have too much swing in the temp, mount your thermostat closer to the light, above it is where mine is at.
Also, my thermostat tended to drift over a period of days. On about day 12 I drilled a hole in my incubator right above my thermostat and took a small screw driver and attached it to a dowel and ran the dowel through the hole. That way I could adjust the thermostat without opening the incubator. And I did that alot. This was certainly not a set and forget incubator.
I had a thermometer that I got at
Walmart that would show me a high and low reading so I can tell what was happening while I was away.
I think that about covers it all. I should have made notes during my hatch.
Good hatching vibes are being sent your way.
) 
