what is value of scale_sch for FFT5.0 IP core in IFFT

We are using scaling in FFT5.0 IP Core for 64 transform size,radix 2 
burst mode,natural order,scaling(so get same o/p size as i/p size), i/p 
data 8 bit and expected o/p data also 8 bit. For this we scale for FFT 
in FFT5.0 IP CORE using trial method and using scale_sch="010101010101" 
in this case no overflow and for scale_sch="010101010100" it is overflow 
.But when we give o/p of FFT to I/p of IFFT (as we want to reuse same 
core) then in every scale_sch value there is no overflow. So what should 
be vaule of scale_sch for IFFT. Can anybody suggest me?
Before FFT I am using 50 hz sine wave using ADC and after IFFT I am 
using DAC and I want to remove all noise except 50 Hz component. Can 
anybody suggest me the process after FFT.

varun