Nerdy Flight Planning Question

I seem to spend about an hour a day making flight plans, maybe planning five flights for each one I depart on, because I have to be ready to go now for wherever the weather favours. You'd think after I got the one-way airways sorted out there wouldn't be much to plan, but I have to specify under instrument flight rules what we're going to do on a very non-standard flight. Instead of going from A to B by an efficient route, I'm going from A to a point that I must define precisely, but may depend on the location of the clouds on that day, then hang around in the same reserved airspace for hours, then fly to another arbitrary point to exit, and from there proceed to an airport of landing. An airport that is completely secondary to the purpose of the trip. We really don't care where we land, so long as it is long enough to take off again and they will sell us avgas.

Rather than specifying every photo line, we file "photo blocks" pre-named chunks of sky that you can see if you happen to have an old WAC chart lying around. Photo blocks have names like 093H4, and I file a list of photo blocks with the altitudes we need in each on a special flight plan form, then in the actual flight plan section I write (PHOTO BLOCK) instead of the name of an airway. I can enter the photo block at a conventionally named fix, and I will if there's one handy, but more likely we'll just be entering at an arbitrary point that I specify with latitude and longitude in the form 5100N11230W (ENT). There will be a second fix tagged (EXT) after the photo block, and everything else is like a normal IFR flight plan. Except we don't care where we land, but we still have to put something down.

On an IFR flight plan you specify your true airspeed in one block at the top and I'm used to putting down whatever fiction the manufacturer claims for the aircraft at the flight planned altitude, minus a bit for reality, and just leaving it. ATC knows that I'll climb a bit more slowly, and my initial descent will probably be a bit faster. At least that's how everyone I have flown with files and flies. But there is a mechanism by which you can specify speed changes, and any time you file an altitude change you have to refile your speed anyway, because the format is like this: N175A095 meaning 175 knots at 9,500'. But one day while listening to a departing Westjet flight being given a speed restriction in the climb, I thought about the fact most pilots don't climb into the flight levels by pulling their nose up to Vy with sustainable climb power and waiting patiently. What sufficed on an IFR flight plan down below might not be the best information for one at more rarefied atmospheric strata.

So I called IFR flight data and I asked them how an IFR flight that begins with twenty to thirty minutes of climbing at speeds significantly lower than the aircraft's normal TAS should be filed. The controller had an answer, but I wonder if it would be the same answer across the country and abroad.

What do you think the advice was? Or if you're a controller, what would you expect? I'll tell you what my guy said, in a couple of days.