Is it possible to open all tubes at one time?
 

I select tube one and open it. Then I select tube two and suddenly tube one closes again. Why won't it stay open?

You can select salvo mode and select multiple tubes at one. I haven't looked at the tube to see if they are all open though, but that might work. I've no idea how to set the spread angle though.

select salvo to keep more then one open

Sweet, thanks for the quick response!:)

Does it really matter though? I know in SH3 it definitely mattered, but on multishots I'm not really getting the same "flood tube, open door" lag you got if you didn't open the door first that SH3 had.