When I use the semi stand method I fill the tube up and then place the cap on. You leave the tubes standing vertically (well I do anyway) ensuring that the small airpocket remains at the top away from the neg. If you need to agitate (semi stand) then pick up the tube and rotate/shake and replace it standing up. It uses more solution but at 1:1:400 who cares

I use Pyrocat at 1:1:400 for this method with FP4. My attempts of this with 5x4 negs have all been sucsessful and sharpness is superb done this way

Phill