My suggestion is to stick with the 14000. 250m is plenty of line and realistically, outside of some more specialised areas, you don't need more line. More capacity also means either more braid (i.e. More expense) or fiddling around with backing which I don't like to do.
On the line, Varivas GT is the best casting line on the market - but it is crazy expensive. All other decent braids will do the same job. They won't feel as soft or as nice to cast but will also cost half as much. Only you can make the decision on whether it is worth it but to me, it seems a bit odd to spend more on your spool of line than on your reel.