The layout to choose is mostly due to personal preference. I chose SYM100 because I think that it's the most elegant looking and most functional since it doesn't waste space with a long spacebar. It was also easy for me to get keycaps for, since it only has 1U and 1.5U keys.
I'm using a mixture of DSA profile keys, a mixture of ones bought from previous group buys and from 7bit's other thread where he sells random leftovers. DSA key caps are easy because they don't have differing row profiles, so you can put any key in any row without it looking strange.
USA shipping is covered by 7bit, so don't worry about that part.
I realise I probably lost you at some point, so ask more questions wherever you need to.
![Very Happy :D](./images/smilies/icon_e_biggrin.gif)