i usually shoot in clubs, either black ceiling or tall black ceiling or outdoor rave party. all i need is the bounce card.

using all these diffusion thing only will use up more power of the flash and cause slow cycle and shorter battery life. i have tested from demb, stofen, lambecy, to big arse whale tail, to custom designs, to DIY... wasted a lot money, simple bounce card like a white namecard size is more then enough. sorry if my answer is misdirected from original question. just my experience sharing.

erm... let me think how to answer....

my flash has build in card, and it works in portrait mode due to the head design able to swivel that way.

(indoor)the small card (about namecard size) brings about maybe '15-20%' light forward, which is enough for small fill... if you are in a ceiling room, you will get nice balance ambiance with nice light fill infront. light from above ceiling is always nice and a soft front fill to cancel out the shadow, but not enough to create a shadow of its own.

(outdoor) yes, you are right, but the light will always find its way around, although firing upwards, the light doesnt goes 100% up, there is always some light find its way to disperse everywhere, having small 10-25% fill everywhere. (you can try setting up your tripod+flash and wireless trigger it in your house front yard or empty space with no ceiling, you will see how it spread around the area).... having a big bounce card will bring big heavy light forward, while saving power, it causes harsh shadow. eg, a lighsphere, is marketed in a way telling you the light goes everywhere and give you nice shadow, but to me, i imagine a light bulb, height slightly higher on my head, and i walk around and look at people, imagine the shadow fall on their face with the light source just above my head, the shadow is not natural at all because the light source isnt from the ceiling but rather low, to a point slight higher then them.... to me, they over market their stuff... and people falls into it. then with just the bounce card, this is what i sacrifice, fire away with more power and light lost, but gaining a soft ambient with beautiful shadow due to how the light travels and fall onto them. (sorry im not very good in explaining)

sometimes you need to experiment around to see which style you like, but my advise is always start with the given built in bounce card, you will learn a lot from there. im just sharing my style, you may not like it, you can try test others if it those may suit you