Yes, I agree with Christian and it is possible to adjust the protocol a bit (but as Christian writes we have not done comparison studies). I sometimes coat in RT (for 3hrs) and block overnight instead, if that suits my experiment schedule better.
If you are tight on time, you could instead go for the ELISAPRO kits, with precoated plates. That will save you both time and decrease variability.
Link to ELISAPRO IL6: https://www.mabtech.com/products/human-il-6-elisa-pro-kit_3460-1hp-2
Link to ELISAPRO IFNalpha: https://www.mabtech.com/products/human-ifn-alpha-elisa-pro-kit_3425-1hp-2