If you fasten dessicant paks to the backside of existing duct tape, do it in a way so that if it comes loose, it will not fall inside. If you have it sealed in plastic, dessicant can be placed inside.
Check often to be certain that the plastic is not sweating and collecting moisture on the inside.
If storing for more than a year, I'd squirt oil in each sparkplug hole and turn the engine by hand a few times. I mght also do this prior to storage as well after consulting with the builder.