Qt QGridLayout how to adjust widget width and height - c++

Question

I am trying to adjust a LineEdit and PushButton width in a QDialog window. The LineEdit should be 20 times wider than then button, so it's long enough to show the whole path. Below is my code, I tried several ways, but they all got similar layout (see screenshot). I want to make the Option window at least 2 times wider to make the LineEdit wide enough. How should I do that?
This is my code:
this->setWindowTitle(tr("Options"));
QGridLayout* logLayout = new QGridLayout;
QLineEdit _logPathLE = new QLineEdit;
logLayout->addWidget(_logPathLE, 0, 0);
logLayout->setColumnStretch(0, 20); // 1st: try with setStretch
//_logPathLE->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Preferred); // 2nd try with setSizePolicy
//logLayout->addWidget(logLocation, 0, 0, 0, 20); // 3rd: try with span multiple columns
QPushButton* browseFolder = new QPushButton(tr("..."));
logLayout->addWidget(browseFolder, 0, 1);
logLayout->setColumnStretch(1, 1);
//browseFolder->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Preferred);
//logLayout->addWidget(browseFolder, 0, 20, 0, 1);
QGroupBox* optGroupBox = new QGroupBox(tr("Log location"));
optGroupBox->setLayout(logLayout);
QDialogButtonBox* btns = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
connect(btns, SIGNAL(accepted()), this, SLOT(accept()));
connect(btns, SIGNAL(rejected()), this, SLOT(reject()));
QVBoxLayout* options = new QVBoxLayout;
options->addWidget(optGroupBox);
options->addWidget(btns);
this->setLayout(options);