Seeking a Canadian Zen Cart Guru with CP module experience

I am currently setting up a new wesbite using Zen Cart. I am having issues with setting up the shipping and need someone to set it up for me. This is how I would like my shipping set up: All items from one particular category are free lettermail shipping within Canda. There would be other shipping options as well if the customer requires the items faster than Canada Post Lettermail. If they add a certain attribute to a product in that category then the Canada Post Module will kick in and estimate the shipping charge based on weight. There are two other categories that would have free shipping within Canada but there are no 'add on' attributes so the Canda Post module would not be required in those categories....just 2-3 other shipping options if the customer wishes to receive their order faster than the free shipping allows. Within the same category as the above example, international shipping would be a flat rate...there would be 2-3 flat rate shipping options, depending on when they require their order. I have two other categories that would be flat rate shipping; different modes of shipping options to both Canada and International.