One Room Studio Retrofit - Advise Needed

Hello All, I’ve got a space on the 2nd floor of my detached garage that I’ve been recording and mixing in for a few years now. It’s not your standard shape room, which is why I’ve come here. I’ve quickly learned that I need to suspend my gear purchases and get this room in order or my mixes are never going to translate. I’ve done some meager attempts at taming the flutter and slap back, but nothing worth noting here. I’ve been in sound for most of my life, so acoustics is not completely foreign to me, but with dimensions of this room (shown below), I’m at a bit of a loss, especially with the low end. So here it is… The Current State: The room is about 27 feet long and 16 feet deep. As you can see, the ceiling is vaulted on both sides. It’s about 12 feet high at the peak and about 7 feet below the windows. The walls are parallel. The lower halves of the walls are wood paneling and the rest is sheetrock. The floor is linoleum tile and the ceiling is currently cheap ceiling tiles (not fiber) framed in by furring strips. I would like to redo the walls and ceiling but this is the current state. I would love to do some sort fabric covered cavity with space wood slats, but I know there is science to that, so I’m not attempting it without proper guidance. I’ve got neighbors, but they about 300 yards away, so sound proofing isn’t really a concern. Where I’d like to go: This space is currently used as a one-room recording and mixing space. The desk and drums are placed essentially as the pictures show them. I've experimented in Sketchup with splitting the room into a control room and live room, but 2 factors always send me back to the single room setup. 1st: I'm concerned that the live room will be too small for a full band (4-5 people) to record live. 2nd: With the ceiling vaulted from both sides, I can't figure out how to make the best use of the space. I've tried using splayed wall designs, but when I look at the ceiling, I'm worried it's not the best course of actions. So, unless someone has some ideas that would help convince me otherwise, I'm back at a single room...for now. Down the road I hope to finish the 1st floor of the garage for a live room, and devote this room to a control room only. So hopefully anything I do can be compatible if that happens. I want an acoustically accurate room that will sound live enough to record drums, but more importantly accurate for mixing. I've wasted too much time taking mixes all over the place trying to determine the best levels. I want to be able to mix something in my room and be confident it will sound good everywhere else. As I type this, I’m thinking I might be best served hiring a professional to simply design a room within these walls that will suit my needs. Treating 1st reflections and building bass traps is one thing, but I really want an aesthetically pleasing place that is functional, beautiful and inviting. I don't want it to look like I just added some treatment to fix my problems. I want a room that looks purposefully designed to record and mix. I will do all the construction myself, I would just need a professional design with plans. I don’t know what the going rate for a design like this is, but I would hope it could be done for less than $1000. Electrical and HVAC aren't needed. I can deal with that during construction. I just need acoustic/aesthetic design. Questions: 1. Are the general positions of my desk and drums a good starting point for a single room design? I know it’s always said to point the speaker down the long way of the room, but in this situation, I think that would really detract from the functionality of the room. As well, the ceilings being different, there would be no symmetry above. 2. With the not-so-standard shape of the room how should I deal with the low frequency issues shown in the waterfall? 3. Is professional design my best course of action to get the professional results I desire? Or, am I blowing my needs out of proportion? 4. Is $1000 a reasonable budget for professional design, including drawings etc? I'm sure I'll have more questions, but this is just the starting point. Thanks! Jack