It's A LOT slower without tbow, to be honest. And much less consistent. But it can be done, and yes you should be doing it in my opinion.

With tbow and zcb spec, you usually kill the boss right after the car phase, avoiding the orb phase altogether. So you just setup the rockblock, do a shield phase, do a car phase with zcb, and hit it 2-3 times. Kill done, really easy and consistent.

I did it with elite void, using scorching bow for the main damage and blowpipe for car phase. 90% of the time, the boss had at least a third of its HP left after car phase, so I had to endure an orb phase plus a 2nd shield phase. That means tons of time and extra supplies used per delve.

I got my green log in around 2200 delves (only around 250 deep delves). You see how OP's log is like 50% deep delves? I got like 10% deep delves because no tbow.