Most of what gets written about fundraising trailers is written to sell you one. This is the other thing. Everything here is what I would tell you on a call, with the sources so you can check me.
Most filmmakers treat the trailer as an expense they have to invent money for. On the industry's own budget template it is a pre-existing account with a number next to it, sitting beside four other lines nobody bundles. Here is the actual sheet, the actual accounts, and the one line on it that will get you caught if you quote it wrong.
Several of the rooms worth pitching in have a moving image requirement written into the submission form, in exact minute counts. If you do not have three minutes cut, you are not late, you are ineligible. The requirements, verbatim, and what they actually mean.
The single biggest thing that decides whether your sizzle is good is not who cuts it. It is what you hand them. Most people hand over the wrong material, hold back the right material, and do not know the difference. This is free and it works whoever you hire.
More as I work it out. If there is something you want explained properly, tell me and I will write it.