Nifty and BN ATM Straddle

I am unable to create Nifty and BN ATM straddle in the new version of Streak. Dynamic Strike selection option is not there.

Also Please advise if SL can be trailed once one leg SL is hit.

Also once one LEG SL is hit I want to add one more lot of the another leg (Whose SL is not hit) at MKT Price.

@Streak can you please help?