Congrats on the new mill and welcome to the 833TV club!
1. The preload on the 'thrust' bearings is created from the bolts and hold the handles on. I don't like this design but its a compromise for an affordable machine. Don't just crank the bolts down, you want to torque them just enough until there's no backlash between the leadscrew and table. If the rotation of the handles feels lumpy and bumpy you've gone too far.
2. I don't really understand this part of the design but you have two options. First option, remove the cover from around the belt and pulleys to get easy access to the spline and draw bar. Option 2, if you have a 3D printer you can find my 'Another PM-833TV Thread' and print a wrench that will slide in and grab the spline with enough room to put a wrench on the drawbar.
