why purchase a library? Do you have a entry level person? You can have them make a block library of your own, that will work not only for you but for your clients as well.
Regards,
Namdac
Agree with namdac. Make a block for each symbol then go into your CUI and create a button and button image for each symbol block. Finally, create a toolbar or toolbars to hold all your symbol buttons for easy and quick insertion into your drawings.