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":
Emma RUSS
(Pontypridd, Glamorgan, Wales;11 Nov 1886 - Mar 1949)
George Edward WALTON
(16 Mar 1884 Aston, Warwickshire, England - Jun 1955 Pontypridd, Glamorgan, Wales)
├─John William WALTON
(Oct 1910 Durham, England - Aug 1994 Stoke-on-Trent, Staffordshire, England)
├─Irene M WALTON
(14 Apr 1912 Rhondda, Glamorgan, Wales - Jun 1974 South Glamorgan, Wales)
│ + William H DAVIES
(28 Jan 1909 Cheltenham, Gloucestershire, England - DECEASED)
└─Jack WALTON
(Pontypridd, Glamorgan, Wales;Sep 1918 - Between Oct and Dec 1948)
Gertrude Ellen ALLAN
(8 May 1921 Hinxton, Cambridgeshire, England - 11 May 2019)
└─Graham Douglas WALTON
(1 Jul 1943 London, England - 3 Dec 2023 Margate, Kent, England)
1886 - 1949 (62 years)
George Edward WALTON 
(16 Mar 1884 Aston, Warwickshire, England - Jun 1955 Pontypridd, Glamorgan, Wales)