Disagreeing with your boss is seldom healthy for your career. Oral options stated forthrightly while exuding confidence are the best approach. If pressed for a written opinion do it in Email, since people tend to readily delete old Email messages. Do NOT commit your opinion to a written memo, someone will save it and haunt you with it when you comply with Rule 5. If reality contradicts a past pronouncement change you stance as quickly as you can.
People have short memories, especially for things which they hear.
Your revised opinion, stated earnestly, should be able to convince your listeners that this is what you said in the first place. Surveys have shown that good looking, well dressed, well spoken and physically fit guys and gals succeed much better on the job than, average looking people. And much, much better than geeks and nerds. Do whatever you need to achieve this. This also gives you a chance to express your carefully thought out opinions, which just happen to complement those of the leaders.