hey, don't apologise for all those questions. i'm pretty sure plenty of people will have the the exact same ones.
in the gaming industry, server locations are divided geographically. GENERALLY speaking, if you want the 'best of both worlds' (ie, decent ping from both sides of the coast), then yes, chicago OR dallas are your best options. chicago, traditionally, has always been best for people who live in the north and east, while dallas tends to favour people for the west and south. this will explain why your california member pings better to dallas than to chicago (the fact that the northern ireland guy gets better ping to dallas is a bit of an anomaly, but routing is known to do strange things to ping). as far as i am aware, you cannot change your game server location in tcadmin.
if you haven't already, send a support ticket for this kind of move.
as for cores, they generally will not help in terms of ping/latency. however, a dedicated core will help with server performance dramatically.
i'm not sure about clan donations, so i'll let someone else field that one.
i hope this clarified a few things. if you still have questions, don't hesitate to ask.