PAH design/size question

Hello all - This fall, we are offering Print-at-Home for our season subscriptions. We have already started using PAH tickets for single ticket sales and exchanges, but haven't given the option to receive season tickets online before. We send the entire season's tickets at once, so we are a little concerned that the email might fail to be delivered with very large subscription orders. 

Are there other organizations with experience emailing season subscriptions? If so, have you ever experienced issues with files being too large? (We can currently get our pdf sizedown to 535 KB)

We have pared down our design as bare-bones as we can (no large images, 3 colors etc.), but we want to be able to keep our branding intact on the tickets.  Has anyone had success without compromising the look they want?  Thanks for any suggestions!