I sorta feel like the blind leading the blind here but I'm thinking that if you instantiate it without specifying values, it takes these default values (doxygen magic);
RFM69 (uint8_t slaveSelectPin=RF69_SPI_CS, uint8_t interruptPin=RF69_IRQ_PIN, bool isRFM69HW=false)
In one of my sketches, I use a different slave pin and a different external interrupt so it looks like this (it is HCW);
RFM69 radio(R_SS, R_INT, true);
instead of simply;
where I've defined what the radio ss and int are by the arduino pin numbering farther up.
Your MISO/MOSI pins are gonna be fixed unless your uC has more than one set or using bitbang spi. In either of the latter cases, I think you'd have to edit the value in the library itself.
Forgot this also, the library doesn't care about reset and can be any gpio that you output high/low. Somewhere else, I also define it R_RST for that and have only used it in the init, err setup in arduino. I can't convince myself to quit calling it init.
Anyway, this is what it seems like you're after and I don't think I've goofed on any of it but if I have, here's hoping someone will correct it or delete it.