I don't think it's possible to market-make bonds on IBKR, I do occasionally enter orders there and there are constant trade troughs and non-honoring of quotes. Basically the bond market structure is one giant scam against the little guy. I basically will put in a bid for $101, and it'll trade $100 on ten separate occasions without me getting a fill. Maybe somebody has some order type hints, but from my current perspective, it's a waste of time.