^^Interesting place for the spare tire
You do realize with the car on this angle, you're not getting the diff drained as much as it would be if the car was level - I bet quite a bit still remains. Same thing when refilling it, your level would be off. Fluid level will be low when the car is 'leveled'.
Do it once, do it right. Get some jack stand for all 4 corners. If your car is lowered, then use your ramps to get enough clearance to jack it up.
Also, this type of ramp arrangement is a good way to cook your clutch.
When I do any type of maintenance that doesn't require the wheels to come off, I jack up the front under the K member, place 2 rhino ramps under the wheels, then repeat the same process for the back wheels. I place jack stands all around as a precaution, and leave the floor jack either under the front, or rear (depending which area i'm working under). Probably overkill, but better safe than sorry. End result is the car is as level as the garage floor, which is quite level for now.