I am in a very similar position - starting 1-2 monthly J trips LAX-FCO. I called to sign up for both, with the knowledge that shold there be any resistance by the CSR I would not bother for the Gold Challenge at the same time purely for the 25% bonus on the outbound leg. She had no problem and enrolled me in both.
I had no issue with challenging post Jun 16 as I will most certainly attain Plat on qpoints this year anyway, and in fact should attain EXP by Jul (in combination with the DONE4 I am doing for leisure).