Help Needed : Confusing about Speaker Placement and RFZ

Hello all, So let me re introduce again : Where am I : Jakarta, Indonesia Language : Bahasa (Just to inform you I'm not speak english well) How Loud : Mix and Mastering Mostly, Overdub Vocal (same room), Overdub Direct Guitar, concepting etc. The room is already soundproofed (I already built 2 layer wall, a brick wall (existing) and Double 12mm Gypsum Wall-I can't find 5/8" here) Again I'm still learning how to collect all infos here and Rod's Book to designing my studio layout. It's my bigest investment so far in my audio career :D What I still confuse is how to determine Speaker Placement (Starting point, Angle, Soffit etc) and how to create RFZ from that and the treatment for it. I try Follow Rod's book p 254

Running a line down the center of the room, from top to bottom, is the fi rst step. Then locate the listening position (38% back), which in this case is 7'-1 1/8" back from the front wall. Step 16" back from here to locate the mic for testing, and then lay out your speakers off this point, using an equilateral triangle. The speaker location ends up centered on the 60° lines, 1'-9 5/8" from the front wall. The location of the speakers (in this case) was specifi callydetermined to allow placement of treatments in the corners behind them. At this point, you can begin room testing (if you desire) or go directly to placement of room treatments.

for placing nearfiled speaker in my room : 318cm(W)x394cm(L)X293cm(H) This size is after 2nd layer wall. The Height is measured from existing tile floor to new ceiling. I plan to use 2cm foam mat, 15mm triplex (plywood) then covered by 4mm rubber mat (we call it underlayer-usually used in automobile) then finished with HDF-Laminated Wood Flooring. So the height will reduced about 17-20cm. I also plan to invest on another speaker and like to install them in soffit (next time). BTW, Rod's explaining is for near field and for the case situation described on that page (small room etc). I guess my room also categorized as small room too. I also read in ethan's realtrap web. How to Set Up a Room. So I'm skecthing in Sketchup Soft. maybe we start with speaker placement layout first, Am I Correct? How to layout soffit angle in my situation? where is the starting point for soffit angle? or where should the soffit speaker be? I plan to use Nearfield and Soffit side by side, so I have 2 reference speakers set when I mix/mastering. Please help.... My Nearfiled Focal Solo6be, My Future Soffit : Any 8" Active Speaker :D

anyone?

I guess I did wrong export to 2d graph. Here's the correct one