Hope this is the right place to post this question. I'm going to India and prefer to keep the weight down. I'm taking D300, 12-24, 24-70 and 70-200 AFS VR f2.8. I'm leaving my 105 f2.8 micro home but would still like to have tools for close-ups. Considering the lenses I'm taking: would either a 25mm and/or 12mm Promaster extension tube(s) be better than taking my Canon 500D diopter? Or 25mm ext tube and 500D ? None of the above? Just use the lenses I'm taking? Thanks so much for your help!