How to customize Deploy feature in VS2010 for SQL CLR projects?
for the trustworthy setting you should go to your project and:
Right click on the project - Properties - Go to tab Project Settings -> Catalog properties file - Edit -> in the middle there will be option for set trustworthy on/off.

If you don't need to change the database properties at all at deploy time, then go to the Deploy tab - Deploy configuration file -> uncheck the option 'Deploy database properties' - first option in the list. This should not apply the settings from the 'Catalog Properties file' to the database your deploying on.

As for Vardecimal storage option I remember I saw it somewhere in the deploy settings.. but no clue for the moment, sorry. If I find it I'll get back with solution.
Hope this helps, at least a bit.