temperature profile for ENIG

Hello, I want to ask on suitable temperature profile for PCBs with ENIG final surface finish. I know that it is complex question with many unknowns. When the PCB will be standard 1,5 mm 35/35 Cu and the amount of components will have any influence on thermal characteristic of reflow, what should be the temperature in reflow stage?

I found some formula, where is the melting temperature of solder + 20°C. In case of lead free it will be 228 + 20 = 248°C.

I have temperature profile with maximum 235°C. In one minute it is going from 218°C to 235°C and decrease to 218°C. Then it is in cooling phase.

On panel with ENIG we have issue with wrong soldering, respectively with bad wetting. I made some pads with handle solder and the result is OK. The nickel is cca 3,7 um and Au is 0,05 um thick.

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