I’ve done both 14 day tours but both were before the current itinerary iterations.
I’ve also done a number of back to back tours although not these two. I’m glad you enjoyed the 21 day tour as it was a favorite.
One thing I loved about the 21 day tour was the change of cultures. I realize Scotland and Ireland are different countries but for me there was a certain sameness that ran thru them. I did Best of Scotland after the Southern England tour and i was shocked that I was “castled” out by the time I got north. Your experience may be different but there are a certain amount of ruins on the Ireland tour as well. Just something to think about.
I found I enjoy back to back tours more when I have a complete change of culture. A particularly successful combo for me was Best of England/Britain followed by Paris and the Heart of France. In a discussion with other tour members others have found that this strategy works for them too.
As to which tour to make longer, pick the one you are unlikely to return to, then do the short taste tour to one you are more likely to go back to….says the person who has been back to certain parts of Scotland several more times, lol.
Any genealogical ties to either?