Floor jack has always worked for me. The brake spoons are bent for that reason. If you're trying it with just a screwdriver that might be a problem.
In fact I can get a floor jack and a jack stand in there, and still manage to adjust brakes. Just get the jack as far outward as you can, but not necessarily directly under the U-bolt.
If I'm just adjusting brakes I probably won't use a jack stand. Because I will just lift one tire at a time. If I am also pulling tires or hubs, or for whatever reason want to lift both tires at once, I will always use jack stands.
For those who insist on lifting under the frame, if you are only capable of following a lawyers text in the manual, and unable to apply a lick of common sense, by all means continue with that. We all get by in life as best we can.
