Custom optimize settings in a code

1. I am using uVision 5, C51 V9.52 & wrote a code. It has multiple source files, one of which is task_manager.c.
In it it has three functions:
a) bit_reset()
b) bit_set()
c) rgb_write()

2. These are very time critical need to optimize for full speed, three functions only, rest code I want to be optimzie for size to save overall space.
Whats the way to do that?

3. These settings I do for speed in keil,
a)Use Extended Linker LX51 instead of Bl51
b) Level 8: Reuse Common code
c) Speed emphasis
d) Linker code pakcing(), AJMP

4. These settings I do for size in keil,
a)Use Extended Linker LX51 instaed of Bl51
b) Level 11: Reuse Common code
c) Size emphasis
d) Linker code pakcing(), AJMP

5. I think these are best settings for size & speed. If any other settings, which can increase speed or decrease size, then let me know.

6. How I can do that on global level, I use minimum size setting option, while for three functions, I use max speed setting.