Hello woodspider,
I have two suggestions for you:
1.
There is a PE set for this kit that dramatically improves the model; I
know it's too late for that now, but think about it next time! Here's a
pic of the set (it is manufactured by Mirage):
(@ http://www.mirage-hobby.com.pl)
This is how a sub with PE parts could look like:
http://www.hsgalleries.com/gallery04/typeviija_1.htm
I bought my PE sets at a Polish online store, after finding out that
Squadron doesn't usually sell them (which is a pitty): http://ibg.com.pl
2.
Forget about the waterline and paint the lower hull in dark gray. This link might be usefull:
http://uboatcolours.mysite.wanadoo-members.co.uk/
Nice work by the way!
Cheers,
Chris