I haven't used a band saw in thirty plus years so I don't know enough about them to say that your friend's techniques are any better or worse than those developed by the engineers who designed the saw and developed the accessories included with it.
If he is willing to coach you on using your saw to maximum effect, and it almost sounds like he wants to (the off hand offer of technique advice points in that direction) and you trust his opinion, in your situation I would be inclined to learn from him.
I wouldn't throw the accessories away because stuff like that is really handy when creating custom jigs. Just like Mike, my attitude is 'throw em this way' if you need the space that bad....
In those situations where his opinion differs from that of the manual. I would probably try doing a cut both ways and make my own decision about which provided better results and which was 'safer'. My philosophy on power tools is that if its plugged in, it is a risk, whether turned on or not. Exact details of technique and accessories used to make a cut have a huge impact on 'how much' risk a procedure creates.
With band saws my greatest fear is blade breaks. Keeping my hands/clothing away from the cutting edges & other moving parts is deeply embedded second nature with me.
Enjoy learning to use your new saw. For me, a huge portion of the joy that comes with wood working is found in the learning experience of the journey. Arriving at the destination of 'finished project' is a totally different kind of joy. Generally it means I get to put the object to use, and on occassion it means I actually get paid by the person who will be using...