well let me give ya some other options done up by inovative KM crews.

Mg 131's MG 151 15mm Drilling which were quite effective and used in the med and in the Baltic.
Flakvierling 2cm and late war 30mm's as well

remember the S-booten arm depended on their speed to hit and run at night, the forward arms were removed, 2cm flakzwilling even had the shield removed for a weight consideration and then the 3.7 or 4cm as standard but sometimes a single Flakvierling in 2cm was used and with disastrous effect on Soviet low flyers who were not expecting such a mirage of pumped rounds coming their way. Many times single MG 42's on either side of the armored cabin were installed during a pre-engagement late war