Gnome Startup script

Hello Comunnity,

im new here, but work with Kali since 2 years (not Pro like!).

i have install the new Kali 2.0 few weeks ago and use Gnome, before i use fluxbox.
My Problem is, i cannot fix the issue with my Startup Script.

I want to start on login 4 Terminals with fixed position. With fluxbox and xwininfo never have any issues.
i customize the --geometry but the windows docked not on this definied position, then i try to insert the values manually by
start -> look -> new values. the issue is, after certain value the window jumps to another position as i want to set, instead of right top, its
is on the middle left top.

After searching why its happening, i lost my understanding with this... to less infos for Gnome with this.
Now i read about Kali & Gnome, and there is a "fallback Gnome"? whats means it? not the full Version?

Same with defined Programs, i want to start some Programs in a specific Workspace.

i want to install fluxbox, but then i miss the fine startmenu.

i write this Posting because i cannot overview at this moment the Problem!
I am very grateful for any help or Tip.

TIA
Calv