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":
Robert OWENS
(Abt 1851 Larne, Antrim, Northern Ireland - DECEASED)
Mary O'BOYLE
(1855 Glenarm, Antrim, Northern Ireland - DECEASED)
└─Alexander OWENS
(18 Jan 1885 - 28 Jun 1966 Perth, Western Australia, Australia)
└─Mary O’Boyle OWENS
(1925 - 27 Feb 2013 bur.Padbury, Western Australia, Australia)
William Moncrieff WEIR
(10 Feb 1923 Mount Lawley, Western Australia, Australia - 30 Mar 1995 Perth, Western Australia, Australia)(m. 1947 Perth, Western Australia, Australia)
Abt 1851 - DECEASED
William Moncrieff WEIR 
(10 Feb 1923 Mount Lawley, Western Australia, Australia - 30