"the fact that the convenient was signed by 453,000 does not indicate that 543,000 were prepared to take up arms."

Maybe that should read:

"the fact that the convenant was signed by 453,000 does not indicate that 453,000 were prepared to take up arms."

That would be the same 453,00 presumably who had just sworn to

hereby pledge ourselves in solemn Covenant, throughout this our time of threatened calamity, to stand by one another in defending, for ourselves and our children, our cherished position of equal citizenship in the United Kingdom, and in using all means which may be found necessary to defeat the present conspiracy to set up a Home Rule Parliament in Ireland

Don't know about you Raggy but that would serve as a good enough indication of intent and sign of commitment to me.