We have a Hemisphere 282RK and although it's a different model I understand the Hemisphere series are the same as the Heritage Glen series just with a different marque so other dealers can offer it. Hemisphere also has a 312qbud model. We are very satisfied with our Hemisphere quality, fit, and performance. I don't think you will be disappointed by your choice.
I am assuming by your comment that there are no labels or decals marking the different waste valve locations? the only pics I could find show the services are located between the 2 slides, but that doesn't mean the valves are necessarily in the same place as the outlet.
Also is there only one connection outlet? With 1 bath, inside galley, and an outside kitchen, it would seem odd. We have a rear kitchen so we actually have a galley outlet connection and valve toward the rear of the trailer in addition to the black and grey outlet and 2 valves for the bathroom near the center. If the control panel has indicators for grey 1 and grey 2 as well as black, then there are 3 tanks, and each tank has a valve. Now my galley valve and outlet is actually under the slide when the slide is extended and you have to crawl under it to get to the components. The position of the Hemi's valves are such that they are right next to the frame when in the closed position so until you know where they are by feel, I have to get down on my hands and knees and look for them. The Black and Gray valves will be near the outlet connection for the bathroom, but not necessarily right next to it. Our grey valve is actually about 2 feet behind the outlet.
If you still can't figure it out, call a dealer and ask to talk to one of the service reps.
Hope this was helpful, happy camping!
Mark, Vicki, & Scout THE dog
2015 Hemisphere 282RK
2010 F250 Super Duty
1992 Goldwing Aspencade