Thank you Holch!
Branching Q2 is one of the options I considered, but I am bit wary of doing it, as it will mess the statistics (I will be exporting the answers for SPSS processing).
The hidden questions solution, although complicated, will help me down the road, and keep my data more organized.
So, the overview would be:
Q1 (radio - single choice) ->
Q2a (hidden, equation) -> will take the answer of Q1 and modify....
Q2b (hidden, multiple choice) select two answers on Q2b, based on the equation in Q2a ->
Q2c (radio - single choice) -> will have an array filter, that will exclude non relevant answers, based on the output of Q2b?
Sorry for repeating the workflow you're proposing, but I need to wrap my head around the logic part

Thank you again!