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: Henry WELLS
(15 Jul 1845 Great Bedwyn, Wiltshire, England - DECEASED)
Mother: Catherine FRIBBENCE
(19 Jul 1842 Great Bedwyn, Wiltshire, England - DECEASED)
Martha WELLS
(Abt 1876 Great Bedwyn, Wiltshire, England - DECEASED)
Ambrose Seymour POWERS
(1881 Donnington, Berkshire, England - Jun 1957 Newbury, Berkshire, England)
└─Catharine POWERS
(26 Jul 1904 Great Bedwyn, Wiltshire, England - 1970 Lincolnshire, England)
Edward David BOSLEY
(Jul 1901 Paddington, Middlesex, England - 6 Jan 1959 Newbury, Berkshire, England)
└─Joyce Martha BOSLEY
(2 Mar 1935 Newbury, Berkshire, England - 1 Jan 1973 Reading, Berkshire, England)
Abt 1876 - DECEASED
Edward David BOSLEY 
(Jul 1901 Paddington, Middlesex, England - 6 Jan 1959 Newbury, Berkshire, England)