If you wanna make Ronnie better , the best way is too pick someone who is similar and pinch their stats , you could use Recoba or Rivaldo for him for example and then just tweak them as you see fit.....
I have just used Makelele's stats for Djemba Dlemba as they are similar players and it seems much more realistic than some of the over the top stats attributed to some players when they are completely made up.
Like Bellion's on this forum ... if he was as good as that he may have actually got a game at Blunderland !!
Hope it helps.
W1nky