George, why did the subject of oil consumption come up with your dealer? If you only have 1000 miles, it's too soon to be worrying about oil consumption since it's normal to use some oil during the break-in period.
My suggestion would be to stick with one brand of oil when possible rather than mixing brands. Incompatibilities are probably quite rare, but it is always possible due to proprietary formulas for the additive packages. One reason I chose to use Mobil 1 V-Twin instead of Amsoil was the availability of Mobil pretty much anywhere. If I can't find the V-Twin stuff, I can add the Mobil 1 15W50 automotive oil with total confidence. As for what to mix with SYN3, however, I haven't a clue. IMHO, the best thing to do with SYN3 is to leave it in the bottle and use something else.
Jerry