Auto ads are designed to ignore all your CSS and insert the ads in a consistent way across different sites. There is no way to control the position or margins of auto ads.
If you want more control of your ads, then you should disable auto ads and use traditional ad placements. See Ad placement and how to create it - AdSense Help for instructions on how to ...
You should always link to your canonical URLs for SEO. There is no reason to expose your URLs with index.aspx on them.
They are ugly
They are longer
You would prefer the other version gets indexed by search engines.
Duplicate URLs like this rarely confuse search engines that much anymore. When Google finds duplicate pages, it ignores one and chooses one ...