Reviewed - given the issues that I encountered, and knowing how difficult it is to resolve templating issues in such a complex scenario, I started from scratch and have now completed it.
After years of templating, for the first time I got caught by a simple extra space in an IF statement that had me frustrated for a few hours, grrr.
- eliminated the deprecated ereg useage throughout Storez.
- adopted your idea of templating common variables - thanks for that.
- templated shipping methods that feed into checkout and order display
- templated payment methods that feed into checkout and order display
- templated the customer and admin email advices
Successfully tested many of the possible scenarios.