How do I tell when my squash is ripe?

It’s frighteningly big, but it’s a pale yellow colour. I thought it was a hubbard, but all the hubbard pictures I’ve found online have much rougher skin. This is something more like the bastard love child of a hubbard and a butternut. I’m worried about leavng it on the vine too long, because I’ve heard horror stories of them bursting. The two most common pieces of squash harvesting advice I’ve seen either tell you to leave it until the vine dies or jam your thumb nail into it and see if it can take it. The latter scares me, since if the squash isn’t ripe, you damage it. The third, which I find preferable, is to wait until it is the right colour. But this is a volunteer, so it’s almost certainly not going to be true to whatever its parent is. Are there general guidelines on how colours progress in squash? If this is a hubbard, is pale yellow a phase it goes through before it turns blue? It used to be bluer, but I doubt it’s going to turn orange or something unless it has a heck of a lot of ripening to do. Any thoughts on what I should do?