Exceeding Max Email Address Sizes
Solution
Read this: http://www.eph.co.uk/resources/email-address-length-faq/ The upshot of it is that you should use 254 characters to store email addresses, because that is the maximum allowed in an SMTP transaction. This is specified in RFC5321 (your article says so, and is actually quoted in mine), which is authoritative.
Problem
RFC Standard says the max email size is 320 (actually 256 according to http://www.dominicsayers.com/isemail/). Is there any conceivable scenario where email addresses could end up being bigger than this?