First- I've removed the front dérailleur to go a single ring up front.
This is a temp fix as I'm going to 8 rear..( is 7 now )

1'ST.-I lost the middle ring ramp position ( compared to the arm position ) It's a shimano sg c-46, This prob won't matter as I'm not running a dérailleur, but I'd like to know for my instruction as to reassembly ( marked it w\ pencil and greased it off..darn! )

2'ND.- I am running mostly mid ring 36 t, I will buy a higher toothed wheel for my single- am on the light metal, ramped mid ring- Is it safe to use this way?

3'RD.- can I use a chain ring intended for 6 speed? ( have a nice solid 36 t, no ramp, but is intended 6 rear ) is this a chain width or tooth spacing compatibility issue?

My lbs didn't have narrow chain ring bolts so all I got rid of was the granny and the dérailleur\shifter- am I looking at road bike parts now? ( single front\7 rear?narrow chain issue again, wish I was doing 10 speeds! )
-And does it really matter if spec wise the manufacturer says intended for mid ring use?
As I don't like this thin 36 I'm on, am really just trying to find a larger, heavier duty ring that will fit mid space on the triple designed crank- ( 46 no way ) a 40 mounted mid might fit.

hmmm.. I respectfully ask that you keep in mind that I'm obviously not knowledgeable about gears, so write for the layman..

Thanks jef.