First. For weighted flies use Maxima as it is stiffer than other products on the market and will turn over better. I use Ultrageen except for the 12# which is Cham. That way I always know where the 12# for repair purposes
I use 50# 25#
36" 20#
15" 15#
20" 12#
30# 10#
If you prefer 12# leader than lengthen the 15 and the 12 and skip the 10.
I also use furrled leaders for this purpose. The furled leader is 9' in length and has 4 feet of tippet on it and will turn over anything.
I would also consider using an intermediate polyleader with 3-4' of 10# on the end.