Erni:
I did not know your Tiny core supported the attiny13 ?
The version on my desk (mostly) does. It has some goodies that actually make the ATtiny13 useful. But the core is not complete (no: analogRead, delay, delayMicroseconds, tone w/ variable parameters).
I have used smeezekitty's tiny13 core, which is great, but it would be nice to be able to use your TinyISP.
Knock-Bang should be independent of the core. TinyISP + Knock-Bang should work well with smeezekitty's core (or any other core).