RSRD n00b question

[LordCucumber]

I am running both TMO and RSRD.

Now I have a question. I am in my second patrol in januari 1942. I've attacked a convoy and sank a single vessel. Apparently it wasn't enough to achieve my mission goal, which is to disrupt shipping (that's it, there is no 'end' to that mission goal stated, so I'm assuming I need to get a certain amount of tonnage before it does end?). Having suffered some damage, I snuck off to find other ships elsewhere, as three destroyers turned looking for me. I eventually lost track of them and they lost me.

Now the problem is, with RSRD enabled, I am only getting the occasional seaplane to keep me busy. I realise that the Pacific is a large place, and the Japanese are not everywhere at the same time, so I am wondering, specifically, where should I go next. I'm about halfway down the first half of January just west of the Luzon strait. Where can I find more Japs around this time in the campaign. I 've been searching for a (ingame) week or so and still zippo. Would heading to Formosa be a good idea perhaps?

Thanks in advance from a greatful n00b