Your explanation, up to 300 words per item, should be able to be included with the meeting notice and thus no additional postage costs to the owner proposing items for the agenda.
Absolutely correct. Cut back your points to the 300 words permitted by the legislationand resubmit. Put your other arguments on a Facebook page or suchlike and give readers of your document the URLs. Apart from anything else, most owners won’t read a three-page document anyway.