Need clarficiation on visitor rules _ please help

Hi,

I have written my cover letter with reference to the new visitor visa rules. One of the section says

4.4 The third party may be asked to give an undertaking in writing to be responsible
for the applicant’s maintenance and accommodation. In this case paragraph 35 of
Part 1 of these Rules applies also to Visitors. An applicant will normally be
refused where, having been requested to do so, the applicant fails to provide a valid
written undertaking from a third party to be responsible for their maintenance and
accommodation for the period of any visit


Could someone please help me understand
1. Which section is paragraphy 35 of part 1 in the rules (https://www.gov.uk/government/uploads/s ... _Rules.pdf)
2. I have written a cover letter identifying each supporting documentation to relevant sections of the immigration paragraphs. That should be good, isnt it? Although, I am not sure if ECO will read it as it is 4 pages long. What do you think?

Pleas help
Regards
Vikram