QRMP payment 35% or SA Basis

I am a manufacturer opted for QRMP by default. In January 21 I am having tax liability net of ITC Rs. 8 Lakh, & I had paid Rs. 10500/- in Cash in December 2020 (Monthly 3B). In this case what I must opt, Fixed Sum Method (35% of previous cash liability) i.e. Rs. 10500/- or Self Assessment Basis i.e. Rs. 8 Lakh. Kindly suggest how much I need to pay

Thanks & Regards,

Mangesh Chitnis