Well, a very important question should be asked before I can give any advice is: what is the size of your pots and what medium do you use?
Also, I don't think watering the orchids while they are still wet is a good advice, I am affraid that you come back from vacation to find out that you orchids are suffering dehydration from lack of watering and lack of living roots which is going to make their recovery even harder.
If I was in your situation, I would do the following:
1. Insure that all orchids are in quit large pots that would stay moist for more than 5 days.
2. Insure that all putting mediums observe water for also quit a long time, examples are sphagnum moss, peat moss. But not any kind of bark especially the corse grade ones.
3. Put all orchids away from high levels of light because photosynthesy will force the plant to consumpt water.
4. Reduce air flow, so don't leave the window opened or the fan turned on.
It also depend on the kind of orchid, for example Catts will stand thirst more than Paphs.
Hope you come back to find all your loving orchids happy and waiting for you. All the good for you in your vacation, and don't forget to buy orchids from there.