well the first thing has nothing to do with the printer design.
Nylon ? really ?
Didn't peg you as a masochist :-)

So the most important thing you'll need is a good actively heated print enclosure.
It's probably the hardest filament to use I've come across.

You can use MyMatt nylon - non warp doesn't need enclosure - not sure if it's available in the states: http://mymatstore.com/epages/ec7809....oft%20Nylon%22
Amazing stuff - no warp !
I guess the money you save on enclosure could go towards the p&p from spain :-)

As for vertical versus horizontal - it's entirely down to the materials you'll be using and what direction any stress will be applied to the parts.
Nylon and flexibles tend to have much better layer adhesion than the harder plastics.
Get pet-g right and it's also got excellent layer bonding.
Get it a tad not perfect and it's absolute crap :-)
I've just switched the brackets ona slinging target from pet-g to cheap flexible pla on the gorunds the pet-g broke when hit with a large hammer and the flex-pla didn't :-)