While these aren't monster damage sources it should be recorded what damage type they are.
http://wiki.spiralknights.com/IMF
Notes about shields after one hit:
>50% damage to lvl 1 Ancient plate shield
<45% damage to lvl 4 Omegaward (Elemental Med UV)
>55% damage to lvl 5 Savage Tortoise (Freeze low UV)
>55% damage to lvl 5 Volcanic Plate shield (Fire low UV)
>55% damage to lvl 4 Crest of Almire
Tests seem to point towards them being mainly elemental rather than normal
Let your knight get hit with the rocket. Take note what color(s) the health pip-rectangles that fall off you are. Here is an example. Your method is good, but this way is extremely fast.
I went and got smacked around (EDIT: on elite). Seems to be a small amount of normal with a large amount of elemental - several green bars and one red bar most of the time. Who's going to pay for my hospital bills?