Вы можете установить фиксированную ширину и выравнивание по левому краю.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
layout = QtWidgets.QGridLayout(self)
checkBoxVBG = QtWidgets.QCheckBox("VBG")
checkBoxIREF = QtWidgets.QCheckBox("IREF")
boxVBG = QtWidgets.QSpinBox()
boxIREF = QtWidgets.QSpinBox()
checkBoxZERO_X = QtWidgets.QCheckBox("ZERO X")
checkBox4MOSC = QtWidgets.QCheckBox("4MOSC")
boxZERO_X = QtWidgets.QSpinBox()
box4MOSC = QtWidgets.QSpinBox()
for spinbox in (boxVBG, boxIREF, boxZERO_X, box4MOSC):
spinbox.setFixedWidth(60)
layout.addWidget(checkBoxVBG, 1, 0)
layout.addWidget(checkBoxIREF, 2, 0)
layout.addWidget(boxVBG, 1, 1, alignment=QtCore.Qt.AlignLeft)
layout.addWidget(boxIREF, 2, 1, alignment=QtCore.Qt.AlignLeft)
layout.addWidget(checkBoxZERO_X, 1, 2)
layout.addWidget(checkBox4MOSC, 2, 2)
layout.addWidget(boxZERO_X, 1, 3, alignment=QtCore.Qt.AlignLeft)
layout.addWidget(box4MOSC, 2, 3, alignment=QtCore.Qt.AlignLeft)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())