How would a spousal support waiver read?

Your lawyer is the best person to assist you on this, but such a waiver could read as follows:

Each party acknowledges that he or she is capable of being self-supporting, is self-supporting, and has enough assets and income to support him or her self. Each party hereby waives all rights to make any claim for spousal support in any form, be it for maintenance, spousal support, counsel fees, and any other like claim, now and in the future.

Be aware, that the judge in your particular case may not approve this clause and that spousal support is more difficult to modify.