I think most folks are of the opinion that the UCE engine is still a little old school and that regular or semi-synth is best for the first few hunderd miles to provide a little friction and help break in. Full synth is fine after that and I recommend it for all air cooled motorcycles since it breaks down less at the higher temps air cooled engines generate.
Don't worry about the stuff on the magnets unless you see a really big piece. There will be lots of small shards and fine shavings on there for all oil changes for the first few thousand miles, but there should be less every time. At 6500 miles I basically just get a small amount of fine powder on there now. If you find a really big piece of anything post a pic here with a coin next to it for scale, we'll try to help you figure out what it is.
Scott