At the moment I use a guidescope (fl=200mm) for plate solving but alignment with the main scope is very important.
I want to use a flipmirror on my main scope (C11) but then the fl=2800mm. And thus a much smaller fov.
Would this lead to very long search times with plate solving?
In general yes. In a smaller FOV you have fainter stars meaning the search has to go through a larger database. Nevertheless solving using the main scope & camera will result in flawless centering so it is the best option.