TREC 20-12 and Flexible Financing

[Seth C.]

I am interested in buying a relatively low cost building and I am not worried about financing, but I am still shopping for mortgages and would like to leave my options open. How can I do that using the 20-12 and still remain credible to the seller? My first step is to include a clause that I will not assign, but I am not sure what to put in Paragraphs 3 and 4 or on a 3rd party financing addendum. 

I was thinking of changing $ figures to percentage ranges, but again credibility is necessary. Should I just present the most likely option and include a clause in Paragraph 11 allowing me to modify financing arrangements?