In theory the 8 way ratchet seemed like a good idea, but ultimately I discovered that a simple pin worked much better. I wasted a lot of time trying to develop the ratcheted joint and I got something decent, but it had limited posing options and it was not as durable as I had hoped. I now use simple 5mm pins. the female socket starts as 5mm, but i need to adjust it depending on the material I'm printing with... tolerances for ABS can vary somewhat depending on manufacturer and color additives. I smooth my parts with acetone so that effects the way I handle the parts. I test fit all of the pins/parts before I smooth them with acetone. Then, I wait a full 48 hours after acetoning before I assemble the parts. This give the chemical reaction enough time to fully stabilize. If you start assembling the parts too soon then the plastic is still a little soft and it will ruin the joint tension. Hope this helps.
There are a lot of choices for entry level 3D printers now. Here's a link to the one I use. It's not the cheapest nor is it the most expensive. BUT it is very reliable and seems to work a lot better than many of the others. Afinia 3D printer ----> www.afinia.com/3d-printers