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":
Margaretta Mary Elizabeth IRVINE
(5 Jan 1863 Albrighton, Shropshire, England - 9 Oct 1940 South Perth, Western Australia, Australia)
Harold DAWKINS
(2 Apr 1860 Portland, Victoria, Australia - 9 Feb 1898 Warrnambool, Victoria, Australia)
└─Norman Percy DAWKINS
(1889 Warrnambool, Victoria, Australia - 1969 Perth, Western Australia, Australia)
Zillah Josephine PROUT
(13 Mar 1893 Queensland, Australia - 1967 Perth, Western Australia, Australia)
└─Charles DAWKINS
(Perth, Western Australia, Australia;28 Mar 1921 - 2002)
Hazel May NORMAN
(Perth, Western Australia, Australia;24 May 1922 - 13 Jun 2000)
1863 - 1940 (77 years)
Harold DAWKINS 
(2 Apr 1860 Portland, Victoria, Australia - 9 Feb 1898 Warrnambool, Victoria, Australia)