Well I have to represent my country on two international competitions and i am going to drill two new balls to complement the ones that i already have and i want to know the advice of you guys taking in consideration the 3 patterns that i am going to bowl

well first of all the tournaments:
i am going to bowl the amf world cup in hermosillo mexico: This is a tournament that its known of having a high scoring pattern so maybe its not a THS but its definately not a challenging condition.
And then one week later i have the south american championship and here we are going to bowl on 2 patterns (one long 44ft,and another one short 34ft) preety close of the ones that were used on the world championships on thailand (kegel is going to oil thr lanes).

So my arsenal right now is:
Storm Rapid fire
Storm Agent
Track Slash
Power groove dry/r

I want to add 2 new balls to build an arsenal to cover the three conditions that i mentioned before
I throw about 460 RPM and 17 miles per hour
please feel free to talk about surfacaes that i may need to change to my current balls.
Sory for my english i am from Argentina

I would say the Cell would be a great heavier oil ball. For mediums I would say a Momentum would be nice for a strong control ball then maybe a Rapid Fire Pearl for something a little longer but strong still in the back. Then light oil a Jazz or a Razyr. I would say these plus what you have should cover anything you should see.