650c wheels bicycle (for 5'3 and under)

@smaryka, thanks for the reply. i wasn't too sure about sizing and comfortability when sitting or riding a track bike. havent got on a bike in donkeys years! do you think there is a "huge" difference between 50cm frame with 650c wheels and a 49cm framce with 700cm?

Hard to tell, because it depends. Each brand is different.
With 650c you can make the top tube approx. 1" or a bit more shorter and keep more standard frame angles.
What frame builders tend to do with very small frames for 700c wheels is making the seat tube very steep and the head tube very shallow.
With 650c wheelss the geometry can be more moderate.

Frame height 49cm vs 50 cm doesn't say anything at all.