For a mature buck tube extended out full makes the best sound. To taper it use your hand to cup or muffle the sound at the end of the tube. You can also vary the length and how hard you blow which will again create a slightly different tone to the grunt.

As to the doe calls I would stick to the bleats. I actually don't use bleats to often either, I stick to contact/social grunts, during the rut I may start do tending grunts or aggressive grunts when rattling.

Personally for me a grunt/bleat is not like a bugle or cow call to elk, yes it can work but I prefer to use it when I have a visual or just to add some realism to rattling. One must remember calling will give an exact location to that animal and often they will lead with their nose...so when you blind call be very aware of your surrounding, especially the backdoor! I suspect the reason some say they don't work is they rarely see the deer that smells them!! Young deer may come less cautiously but mature deer are much different. This is not to discourage but rather my viewpoint based on my experience, call calculated(not over call) and be prepared at a moments notice to let it fly. The proper setup to begin with is also essential, don't expect to call a buck out to a large opening with a simple toot on a bleat or grunt...setup in a good area that transition deer and offer safety to move freely and you'll find more success.

Best of luck!!