critique recipe

hey guys this is my first post on this really great site. im on my third brew after doing coopers real ale with brewing sugar and coopers irish stout with light spraymalt.

this time id like to add some specialty grain. i was thinking of this
coopers dark ale 1.5kg
light dry malt extract 1.5kg

chocolate 200g
medium crystal 200g
roasted barley 100g

and im undecieded on nottingham or us-05

any thoughts on steeping times especially and anything else greatly appreciated

ok so from what ive been reading online the best way to go about sprucing up my kit with some speciality grain is to cold steep the grain for about 12 to 16 hours. sieve off the grain and add to my wort in my fermenter and continue as usual.

what do you guys think of the ingredients im using?........some good flavours there?.........right quanties?

any input appreciated greatly

thank you