The paper length is not relevant since the chart flows from one page to the next.
Mobile
in.
mm
Portrait
2.75
70
For smart phones, not for printing
Landscape
5.5
140
For smart phones, not for printing
USA & Canada
in.
mm
Letter Portrait
8.5
216
Also Legal Portrait
Letter Landscape
11
279
Legal Landscape
14
356
Also Ledger Portrait
Ledger Landscape
17
432
International
in.
mm
A5 Portrait
5.82
148
A4 Portrait
8.25
210
Also A5 Landscape
A4 Landscape
11.71
297
Also A3 Landscape
A3 Landscape
16.54
420
The Text+ programs assume that the right and left margins are each about 25mm (1/2 inch) wide.
On the Format for Printing page, differences in page margins can be accommodated by the "fudge factor":
James Lilley SOMMERVILLE
(7 Aug 1887 Wishaw, Lanarkshire, Scotland - 8 Feb 1946 Liverpool, New South Wales, Australia)
Elizabeth Drysdale HAY (1 Apr 1887 Edinburgh, Midlothian, Scotland - 1 Mar 1978 Mona Vale, New South Wales, Australia)(m. 4 Nov 1910 Corstorphine, Midlothian, Scotland)
└─Elizabeth Hay SOMMERVILLE (13 Jan 1911 Corstorphine, Midlothian, Scotland - 10 Jun 2004 Springwood, New South Wales, Australia)
Ernest Wallace HALL (8 Jun 1903 Battersea, Surrey, England - 30 Apr 1982 Narrabeen, New South Wales, Australia)(m. 17 Nov 1934 Chatswood, New South Wales, Australia)
1887 - 1946 (58 years)
Elizabeth Drysdale HAY 
(1 Apr 1887 Edinburgh, Midlothian, Scotland -