This is where accidents start to occur; when pilots start to deviate from established SOPs, in favour of their own idiosyncrasies, which haven't proved to be safer, nor more effective. With this tendency to always calculate takeoff performance figures with 'wet runway' selected, say V1 for a dry runway is 140kts, whilst wet is 125kts. Let's say that runway is in fact dry, but this Captain is electing to use the wet runway calculations. If you have an engine failure/fire at, say 132kts, you are able to stop on the runway if your V1 was 140kts, not so much with 125kts. How is it safer to takeoff with a failure, all because your Captain elected to use wet runway calculations? Expect to takeoff normally but be ready and have the appropriate configuration in an event of an emergency, such as using the correct speeds.
Generally, you should trust the numbers that your landing calculator has spat out, particularly if the runway is short.
Having your engines at takeoff thrust for almost 5,000 feet is an awfully long time to have them at such setting.
I find it unacceptable if he is doing many things without telling you or without discussing it with you. How can you and your crew share the same picture/idea if you don't convey what you are doing?
Unfortunately, like others here have said, just sit down, smile and go along with it, unless it is abundantly clear to you that there is/will be an issue.