I can have a go at finding the other components of shield emitters at 50 quality, but finding two 50 quality modulator's might be tricky, but it's not that vital. A secondary modulator simply adds 50% of that modulator's shielding to the finished emitter, ignoring decimals. So a 50 quality HF modulator will add 2 very low shielding, 6 low, 25 medium, 37 high and 48 very high. It also doesn't add anything to the finished shield's value, although it does add to its weight.