I have designed a two-sided (components on both side) 4-layer SMD PCB that I will reflow with my solder oven. To do so, I am planning to use high-temperature leaded solder (MG Chemicals 4860P, ~250 C) on one sided and then reflow the other side with low-temperature silver-based solder (Chipquick SMDLTLFP15T4, ~165 C). Reference to the idea: https://www.instructables.com/id/Making-double-side-boards-in-reflow-oven/
I noticed earlier that the Chipquick solder does not want to reflow or stick to the PCBs I normally order from PCBWay or JLCPCB with HASL (leaded) finishes (default). The leaded one reflows extremely well.
I was wondering what type of surface finish would be optimum for both types of solder. Surface finishes offered are: HASL with lead, HASL lead-free, Immersion gold(ENIG), OSP, Hard gold, Immersion silver(Ag), ENEPIG and None(Plain copper).