32 bit mode for PSP & 16 bit mode for TV screen???

[MysticWhiteDragon]

I am trying to incorporate TV out into my program. I want to use 32 bit depth (8888) for output to the PSP and 16 bit depth (5551 or 5650) for output to the TV. This is because I have a SDTV and want to use VRAM rather than system RAM since it processes faster. I can get 10 fps displaying system RAM in 32 bit mode and 15 fps in 16 bit mode. Since VRAM is faster I hope to be able to achieve higher frame rates.

Here are my questions:
1.) How should I define the base address of VRAM (if it matters)?
u32*, u16*, void* (0x40000000|0x04000000)

2.) sceGuDrawBuffer() specifies a way of telling the color bit depth do draw, but how do I do this to the display buffer and make it possible if to change if a user switches between the PSP screen and TV screen?

3.) Which mode it better for displaying to the TV (5551 or 5650)? I am assuming since I am just copying and scaling it that I don't need the alpha bit so 5650 should be better right?

Any help is appreciated and thanks in advance!