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":
Father: John Wesley SMITH
(18 Oct 1847 Edmonson, Kentucky, USA - 5 Dec 1924 Ringgold, Iowa, USA)
Mother: Eliza RAY
(25 Jan 1854 Berwick, Warren, Illinois, USA - 1 Nov 1930 Buchanan, Missouri, USA)
Lena May SMITH
(3 May 1883 Berwick, Warren, Illinois, USA - 1942)
Herbert Ward BASTOW
(28 Nov 1884 Washington, Ringgold, Iowa, USA - Jan 1966 Mount Ayr, Ringgold, Iowa, USA)
└─Charles Wesley BASTOW
(2 Dec 1910 Tingley, Ringgold, Iowa, USA - 7 Mar 2003 Mount Ayr, Ringgold, Iowa, USA)
Helen Rosalie JOHNSON
(27 Aug 1923 Lamoni, Decatur, Iowa, USA - 15 Oct 2004 Mount Ayr, Ringgold, Iowa, USA)
1883 - 1942 (58 years)
Herbert Ward BASTOW 
(28 Nov 1884 Washington, Ringgold, Iowa, USA - Jan 1966 Mount Ayr, Ringgold, Iowa, USA)