Depending on your age you might get a second or third chance, once every thirty or forty years.
You should still pursue getting advice from a professional forester not affiliated with the logger.
I see this all too often... A landowner tries to save a few bucks by doing a sale on his own, then is completely unhappy with the results. All too often it isn't the contractor's fault, the landowner silmpy doesn't know what he wants or what can and can't be done with the equipment available. No disrespect meant to the OP, but it seems that until very recently you hadn't even considered a harvest, so you might want to slow down and think about what you want.
What type of equipment are they going to be using? Will they be cutting with a chain saw, or will it be a mechanical operation where the trees are cut with a machine and hauled ojt to the yard to be limbed and bucked? What if anything, do you expect them to do with the slash; i.e., tops and limbs? Will they be selling the trees for the highest value (more returns for you), or running it through a chipper?