Castledine looks to be doing at least as well on the face of it. Regardless i think loaning either would be totally pointless, if we want to pay a small fee then crack on.
I think Castledine is more of a 10 with CD being a RW/LW (mainly Right) CD dribbling stats are really something and his creativity stats.
Even last season for Blackburn he had good dribbling stats and seems to have good work rate as he has good recoveries/90 which shows he tracks back a lot.
Castledine seems to have weaker dribbling stats but wins a lot of free kicks, has goos shooting stats and is good in his duels on the ground and in the air.
So they seem to be different sorts of players which both on loan in January could be quite good but Im not sure we need a 10, i think we need a winger more, as Eccles and BTA can play in the 10 and when both fit Castledine doesnt get a sniff for me. Although both are top prospects CD has championship experience (23 games ~700 minutes)