I don't understand much how sitemaps works and i really love the keep it simple on your plugin. Thanks a lot for that :)
About this issue i tried other plugins (yoast, google sitemaps xml) and don't know why or if it's the right way to do it but they limit sitemaps parts to 1000 articles.
I'm not sure how many articles we do on a monthly basis but maybe 50 a day or more. not sure.
This wway with 500 error on webmaster tools google is giving error because it cant crawl those sitemaps.
Any thing i can do about this?
many thanks again.