I wrote this to another topic:
"Base sizes are fixed in Oathmark, however, their importance is in my opinion not that high. The unit width gives the number of dices (mainly 5), but what happens, when its not 25mm, but 20mm, or 32mm? The unit will not be 125mm, but 100mm or 160mm, but it has still 5 dices. The unit width is only real important in some rare situations: can it be charged or not, is it a flank attack, or not. More wide or narrow can be good or bad, depending on the situation. But if You dont play competitively, all this can be discussed... The length is even less important: can it be flank attacked or not? But here is clear: the longer, the worse (unless You want to block something)."
https://leadadventureforum.com/index.php?topic=127430.510But if your cavalry is on circle bases, thats much more wide, and will make difficulties, as Pattus Magnus wrote.