The same.
 
Only speed increase using differing amounts of ram depends on your motherboard (wether it has some incompatibility), caching problems, or if your using single-sided/double-sided ram.
 
For instance interleaving only works on double-sided ram.

More there is more can go wrong...
keep it simple and stupid. go for singel 256Mb

Normally on via chipsets you'll get the best speed if you have 4 way bank interleving on, and 4 banks + of memory, so 2 double sided 128Mb sticks would give the best bandwidth
 
Not sure about memory management by intel

I'm sure that's not quite true, so I'll go look it up...
 
Here we go (from http://x-bios.3dgames.mu/index.php3?shpage=art&artname=memenabler):
 
Why do I need it?
ViaTech (www.viatech.com, or www.via.com.tw) has included a "memory interleave" feature in their chipsets since 1997. Many motherboard makers chose not to enable it, however. This feature can drastically improve the speed of memory access, but only if it is switched on.
 
I only have one memory module. Can I use interleaving?
Generally, yes. In this kind of interleaving, the chipset can remember the location of up to four recently-used "pages" of memory on the module and can return to them instantly. Depending on the chipset, it can also remember the last four pages per module, for a total of sixteen pages. When the CPU needs to access these pages, the VIA chipset can access them quickly without having to calculate their location.
 
The amount of interleaving depends on the size and type of the memory chips on the computer's RAM modules. SDRAM is required. If the chips on the modules store 16 megabits each, the VIA chipsets can achieve two-way interleaving; if the chips are 64 megabits, four-way interleaving is possible.

I would say 4x64 gives the best performance...if you find a board with 4 banks, that it.

If you can, use just one bank as that provides less overhead on the memory controller (but you will probably not notice this anyway).

Use the 256. That way you have more room for SDRAM.
Oh, and I belive the apollo pro 133A can only use 4 banks if it's PC100. At least on my VP6 it does.