Shapeways Help/Tips

Just started with shapeways and I'm wondering if any veterans here can give some tips or just things to look out for in general
Some questions I have off the top of my hat is whether the plastic shrinks after printing and if so how much?
Also what's a good distance to put between the ball and socket?
On another note:
I'm working on a replacement sword/tail for TFP voyager predaking and this is my progress so far. http://shpws.me/oAlC I've made some changes since but didn't update the model.
I wanted the sword and tail to be articulated and still fit the original T shaped peg on voyager predaking. I also redesigned the peg so he can hold it better in robot mode, hopfully... can't confirm until tested...

Some questions I have off the top of my hat is whether the plastic shrinks after printing and if so how much?
Also what's a good distance to put between the ball and socket?
On another note:
I'm working on a replacement sword/tail for TFP voyager predaking and this is my progress so far. http://shpws.me/oAlC I've made some changes since but didn't update the model.
I wanted the sword and tail to be articulated and still fit the original T shaped peg on voyager predaking. I also redesigned the peg so he can hold it better in robot mode, hopfully... can't confirm until tested...