Well yesterday I tried the square board. Following the pattern was easy, but getting the tension right was more difficult. I also had a little problem with finishing off - realised I should have stopped a couple of rows before as I had a slant on it, but didn't want to risk trying to undo it (mainly because I had already undone a couple of attemps at beginning of the bracelet and had to restart!). However, I know what to do next time - I must finish when the sequence gets back to the start, rather than carry on until I have run out of cord.
I shall try this flat bracelet again, but think I might try it with thinner material such as embroidery silks or even wool which will have more "give" in it - hopefully I will get a more even finish then.
Must confess that I do prefer the round board bracelets, but hey you don't know until you try do you!