The trick with shinai and shield is to treat it just like an arming sword and buckler. Use the same combinations, but with more emphasis on the falso to cut over the shield. Standard defenses such as showing a montante (i.e. dall’Aghocchie’s Guardia di Testa) and running off when they clash are also feasible.
Now that I’ve seen the mistake in Agrippa’s Prima, that stance has proven to be most devastating. It can be made even more so with the use of a long blade. I’ve got 5 sergeant’s list fights left before I move into the AE knight’s list. I figure I’ll switch to a shorter blade with each win. If I do really well that means the last fight will be with daggers. Not sure how that’ll work from prima, but it would be fun to try.