Re: removing a fuel tank
I just did mine. The syringe didn't work for me (maybe not big enough) so I used a bit of pipe, stuck it in me mouth, and sucked. Worked just fine, but a bit long winded (no pun intended). A one-way valve on the sucker pipe would have let me draw the vacuum, and knock off for a fag and a cuppa, but I didn't have anything suitable. They say you can damage the diaphragm if too much vacuum, so just drew enough to get the fuel flowing and no more.
Have to say, after pi55ing about doing that, I still got loads of fuel peeing out of the crossover when it was disconnected, so be ready for that (I wasn't).
Have a short length of fuel pipe made up, blanked off at one end with a suitable bolt and hoseclip. Get another, longer length of pipe, and fit a bit of tube of the right diameter inside it, and hoseclip it on. Leave enough of the tube sticking out, so it will fit into another length of hose (the crossover pipe). Stick one end of this long hose into your fuel drain can. When you pull the crossover hose off, stick your thumb over the crossover hose, and your blanked piece of hose over the tank outlet. That's one side sealed off, and you don't have to worry about it.
Remove thumb, and replace it with the bit of tube sticking out of your drain hose. That drains the excess from one side. When it's stopped draining, remove the tube, and transfer it to your short length of hose on the other side, after removing your blanking plug (you'll need your thumb again). Make a note to buy one of these quick release clamps for next time, as mentioned above....