multple choice in horary

1
Hey people

Theory question I can never get this straight.

Let's say querent asks will I remain with xxxx or meet another?

Logically, lord of 7th is the current and any planets in 7th is a new.
But I was reading a horary book where it states that use Sun to rule a new man unless Sun is taken by a querent.


My other question is .... is there collection of light among venus/mars (both significators) and saturn as the collector of light?
The reason why I am asking is Mercury changes signs and catches up with Mars before Mars gets to Saturn. Do we ignore Mercury since it is in another sign or use Merc as a cut off light?

Thanks
CD