This is an experiment :)
My suggestions include:
1] All money goes into the pot, with an equal amount each for personal use (not kids' treats!)
2] Shared ownership of everything in writing.
3] Three holidays a year - one for her, one for him, one together without DCs, one family together.
4] Weekly date night.
5] Daily compliment, both ways.
6] Weekly family conference, for grievances and plans.
7] No justifications in response to criticism, unless an explanation is needed for practical reasons.
8] Stupid questions like "Where are my keys?" get sensible answers like "I don't know."
Additions, anyone?