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":
David Thomas ASTBURY
(15 Jul 1880 Amherst, Victoria, Australia - 16 Nov 1949 Western Australia, Australia)
Mary Coutts STEWART (21 Nov 1880 Wehla, Victoria, Australia - 2 Dec 1958 Perth, Western Australia, Australia)
└─David Stanley ASTBURY (30 Jun 1914 Narrogin, Western Australia, Australia - 4 Aug 1988 Trigg, Western Australia, Australia)
1880 - 1949 (69 years)
Mary Coutts STEWART 
(21 Nov 1880 Wehla, Victoria, Australia - 2 Dec 1958 Perth, Western Australia, Australia)