PC <=Link1=> Arduino Uno as ISP <=Link2=> Custom Board with Attiny
Link1: Normal USB cable
Link2: consists of:
6 wires following that tutorial. Can successfully program and debug with leds (painful)
2 wires Tx/Rx driven by SoftwareSerial from Attiny, and connected to Uno pins 0/1 in a cross manor
Although the Uno runs as a ISP as intended, I need to extend its functionality to forward the serial link to the Arduino Serial monitor for more productive debugging abilities.