QRep1.Page.PagerSize := ??? Trocar tamanho do papel no QRep.

é só declarar a unit QRPrntr na uses e pronto:

vejam

QReport.Page.PaperSize := A4;
ou
QReport.Page.PaperSize := LetterSmall;

Vejam as opções:

TQRPaperSize = (Default, Letter, LetterSmall, Tabloid, Ledger, Legal,
Statement, Executive, A3, A4, A4Small, A5, B4, B5, Folio,
Quarto, qr10X14, qr11X17, Note, Env9, Env10, Env11, Env12,
Env14, CSheet, DSheet, ESheet, Custom)