having used an extended run tank many times
1) you don't need a full tank to start, but you do need some fuel in the tank. Having it full makes it easy to see if the line is indeed working and the system has developed enough vacuum to pull fuel in.
2) I've never used a primer bulb. Now using one will get fuel flowing quicker, but isn't needed unless you have very little fuel in the tank and a very very long line to the external tank.
One comment. it is vitally important to have a cap that seals well. with a bad seal, you won't develop vacuum and won't draw fuel. May seem trival, but it is harder than one may think to have a good seal. any wrinkle, cut, void in the seal material and against the cap and the honda input and you will get a leak.
If you have a good cap, (not all the ones available on line are equal quality) it's "easy peasy", a bad cap, lots of frustration.