I daily drive a F150 Supercrew with the 5.5 foot box. Used to work in downtown Minneapolis, and while I used the bus most days, I did park downtown 30+ days a year, and I attend sports events (well did before last year) and parked all the time in ramps. I had my list of favorite ramps to park in, and knew the spaces I liked the best.
As noted above, it wasn't the space itself that was usally an issue -it was the width of the drive aisle and other cars behind me - such that I didn't park in a spot that had a suburban where I needed to back towards it.
Locally, typical parking spaces are required to be 20 feet deep or have wider drive aisles. There is no free lunch.
In the spot you are parked in, the expectation is the back of the truck is inside the space - not the front within the lines as you've parked. You'll find a lot of places cheat of the painting of lines - paint costs money...