A little slow to reply, Cory, sorry about that!
But yes, I have seen the info at Scale Mates but unfortunately, they just have the instructions for the 20mm equipped version, but nothing on the Bk5.
The Meng kit is slightly different, though informative.
I think what I may have to do, is research a little as to which units used the Bk5 equipped Me410 and go from there - I know the Me410 well enough, that I can assemble the kit as the A1/U4 without the instructions...my kit does have both the standard windscreen and the windscreen (and sight assembly) for the cannon armed versions...