goodroi - 11:15 am on Aug 13, 2010 (gmt 0)
#1 - You dont have to submit the sub sitemaps but i would since it takes 5 seconds.
#2 - To boost your page crawling:
a) Do more link development, there is never enough
b) Make sure your pages have great internal links, turn your site into a spider web
c) Boost traffic on your site, google toolbar users can impact your crawling. Some people use PPC to achieve this.
d) Make sure you have SIGNIFICANT & UNIQUE content for every page.