Mate I wouldn't bother sanding past 600. I stop at 400 most of the time.
I clean with methylated spirit, the start with thin mercury flex and lightly spray mercury (or starbond) activator between each coat.
If the timber has an open grain like wenge or pheasantwood for example, I'll do 2 medium to fill in the voids, activator, then wet sand 1200 until completely dull and smooth. I check on the reflection on an angle to see if this has been achieved. Clean with metho and start the thin process again.
Once however many layers are desired (8 to 10 is plenty) it is very important to wet sand 1200 to completely dull the finish, lateral wet sanding with lathe off also. Check reflective light once again by looking at the blanks from a horizontal angle and make sure there is no shiny spots visible. (Leaving these spots now will result in un even shine on completion).
I thin wet micromesh sand through the entire grits, finishing with auto wax and shine on paper towel, then buff with a soft rag.
I have tried dozens of different techniques, this one is fail proof (for me anyway). I should mention that I use 2 drops of thin ca on paper towel (store bought) per layer, I keep the speed on fast, which others will disagree on, I find i get the same results at any speed, and I have a manual lathe so I may be a little lazy with this part! Haha. But it works for me.
You will end up taking advice from about 549.3 people, and combining ideas from a few to achieve your finish.
Start with the brand, there are a few good ones, I've found mercury flex to be excellent.
Now next step, once you have polished, make sure to have a piece of 1500 sandpaper, and sand the ends in a circular motion on a solid surface applying light pressure. This eliminates the chance of the ca laminating under pressure from assembly. Always check the smoothness of the ends before assembly, make sure they are perfect. Also a good tool to have is a chainsaw file. I give the tubes a quick file before assembly just to make sure that the parts don't need excess force on pressing, which can lead to the ca moving and buckling, an extremely frustrating thing, there is nothing worse than creating a perfect ready to assemble piece and ruining it on the last step of the process. I've had my fair share but I think you need to experience that to really make sure that this step is done every single time.
Lot's of things to take in, but if you practice the same process many times, it will become second nature and you will be knocking them out of the park!!
I've found starbond and mercury flex are compatible. Be careful on other brands as they can work against you.
Cheers!
Casey