This was mentioned in various comments by various Staff. 1.) All pledged payments are paid for when the campaign closes. 2.) There will be a survey/opportunity to add items during each wave for that wave. (unknown if you can add items during wave 1 that ship during wave 3.) (unknown if addon items shipped during wave 1 can also be added for wave 3). 3.) You pay for shipping/taxes/vat for each wave independently - no combined shipping discounts or other reductions.

Most of what you've asked is in the FAQ tab... You can change pledge when the manager opens, you can also add add-ons anytime in the pledge manager until the wave closes for that particular item. This has been discussed often. This means you can break the payments up as much as you like as long as it's before the waves close for those items. Shipping costs will happen when they know exactly how much shipping will be, probably when it's time to ship. They've already mentioned shipping will be charged for each wave and there's no opportunity to delay for one off shipping.