I would wait if someone requested it and communicated with me. Communication & and being honest goes a long wayIf you say the words...be a man of your word and follow through. If I say I will take it...I mean that I will be there as soon as we can agree on a convenient time to meet. On the gun I just bought...the owner had to wait from Thursday until Sunday for me to get there. But we met at the agreed time and all is well.
One day is enough. I check my e-mail and PM's quite often if I have something up for sale/trade. They won't have to wait more than a few hours to get a response...and I kinda expect the same in return. Overnight...that's fine. Come on the site and not respond? I am on to someone else.