I know this thread is a couple of weeks old, but for what it is worth, I just finished my 3.8 hardware build. Soldered by hand using a 10x "watchmakers loupe" to see what I was doing. Use "no clean" or "water soluble" liquid flux to make life easy. Be sure you get the polarity of the LEDs right - little green lines on the right for the ones I got. If you bridge some pins, just add some flux, wipe your tip clean and start by just trying to draw the solder down the legs. Your tip will usually grab some solder off. If that doesn't work, use some copper wick, clean them pretty good and rework the legs.
It is a bad ass feeling to hand solder tiny stuff and see the board light up when you finally plug it in.