You're describing one of the issues I face all the time. One of the things I did was to buy a swivel elbow, (RhinoFLEX Clear Swivel Fittings - 45° Fitting - Camco 39847 - Sewer Fittings & Adapters - Camping World
) and a hose support (15' Flexible Sewer Hose Support - Four Corners 48565 - Sewer Accessories - Camping World
). Between the two, I can fine tune the angle of discharge for those places where I'm near the same height as the sewer hole (as you put it, I don't know what they're officially called either). In most cases, this leads to me having an almost flat run.
Next, when it's time to dump, make sure you dump full tanks. I fortunately have the black tank flush installed on mine, so I use that to fill the black (if it's not already full) and then let 'er rip so the most pressure as possible from the weight of all that rushing water is going to overcome the fact I don't have gravity helping me. When it looks like it's running clear, or the elbow shows it's just not moving anymore, I close up and let the tank fill a second (and sometime third) time.
If I'm close enough to level that my elbow drains, I'm done with the black once it runs mostly clear from a fill'n'dump. If I really have to go uphill (like you described) then I'll remove the hose support and 'walk the slinky' as I call it to do what you did, fill the hose, lift to dump, fill the hose, lift to dump. It's important to start near the tank and work the 'lifted' portion towards the drain. I've seen people who just lift in the middle. All that does is dump 1/2 the hose back into the tanks.
Once that's done, I put the hose support back into place (if removed) and dump the grey. I don't bother doing any flushes on the grey, except for my end of year shutdown where I'll run a couple of taps to refill it a few times. Again, if the hose isn't draining well enough, then I have to do the 'walk the slinky'.
An alternative I've been considering is a macerator pump, but really, with the process above, I don't have to 'walk the slinky' all that often, or at least not more than one or two times, so it hasn't been inconvenient enough to look into one.