Regarding FFT & IFFT in VHDL

Sir
I am trying to use FFT 5.0 core in xilinx10.1 as follows for 50 hz 
SinWAVE(THROUGH ADC)for noise removal
1. 64 Transform size
2. Radix-2 burst mode
3.I/p data width 8 bit
4.Scaled
5. Natural order(without cylix prefix)
I want to know what is the value of scale_sch for FFT and IFFT for 
getting O/P width same as I/P width i.e 8 bit in my problem. As I want 
to use same IP core for FFT and IFFT.Further I want to use inverse FFT 
for the O/P fft i.e XK_REAL AND XK_IMA.and display the same sine wave 
via DAC. So what is the procedure after FFT.Should I remove all real and 
imaginary except fundamental frequency i.e calculated by xk_index.and 
give this to FFT core(for inverse FFT) or anything else, kindly suggest 
me
bye
Varun