This is for alterIW, for 1.1.195 it's the exact same method.
Scan for strings with OllyDBG, search for CG_Fov within those and follow the result.
The mov dword ptr ds:[addyhere], EAX is ALWAYS the addy you'll need.
0x9FFC08 will be a pointer to a dvar struct, the only thing you need to know about it is that the value of the dvar is located at +0x10
004E111D |. A3 08FC9F00 MOV DWORD PTR DS:[9FFC08],EAX
so here's our assembly code:
or if you don't like assembly:
mov EAX, DWORD PTR DS:[0x9FFC08];
mov DWORD PTR DS:[EAX+0x10], 90;
DWORD *fovPTR = (DWORD*)0x9FFC08;
DWORD *fov = (*(DWORD**)fovPTR)+0x10;
*fov = 90.0f;