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":
Emily Matilda DAVY
(14 May 1876 Portsmouth, Hampshire, England - Jan 1944 Cambridge, Cambridgeshire, England)
George Harold WOODROW
(3 Mar 1873 Pakefield, Suffolk, England - Jan 1952 Cambridge, Cambridgeshire, England)
└─Herbert George Davey WOODROW
(23 Jun 1901 Lowestoft, Suffolk, England - Apr 1971 Cambridge, Cambridgeshire, England)
Florence Muriel BLOWS
(Cambridge, Cambridgeshire, England;14 Dec 1908 - Between 1951 and Jan 1953)
1876 - 1944 (67 years)
George Harold WOODROW 
(3 Mar 1873 Pakefield, Suffolk, England - Jan 1952 Cambridge, Cambridgeshire, England)