1) Not sure the OP or overall thread fits for the "Did you know?" section...
2) Even faster still to accept one trade over multiple trades...
3) Offering a big trade instead of many smaller trades only works if there is someone capable and willing to take the big trade. Otherwise, splitting into smaller trades allows multiple people with smaller capabilities and willingnesses to complete.
For T123 goods, recognizing that these are goods traded by cities of all levels, I almost always place my trades in a series of increasing sizes rather than several equal-sized lumps. I also place my trades at a 101% rate, so they are 3 star trades. Since I am on frequently, I will refresh smaller offers when they are taken.
101:100, 202:200, 400, 800, 1600, 3200, 6400, 12800, 25600, 51200, and sometimes 102400, 204800 and 409600, depending on my needs.
This approach allows someone to accept a trade for nearly any value they want. Small player who only wants 100? There you go. Middle player wanting 10,000? pick 6400, 3200, 400. High player who wants it all, sometimes up to nearly a million? Take it all. I spent a much longer time playing while not in a Fellowship, and had to survive on trades in my local group, and I found that this strategy worked slowly but eventually. I'm currently in Chapter 16 and continue to do this for the benefit of all my neighbors and Fellows at their various capabilities.
For T456 goods, since players produce and need it in higher quantities to start with, I tend to place trades in 10,000 units.