Is transiting at DPS airport easy?

I plan to fly from Singapore to Townsville on the 9th of November and board the Jetstar flight from Denpasar to Townsville at 1:10am on the 10th of October.

I am unable to book this route on one ticket (Otherwise I'd have to fly via Brisbane and would not land in Townsville till after 10am) and need advice with the flight from Singapore to Denpasar. I won't have baggage and I won't be able to online check-in for the Jetstar flight so I'll need to make the 45-minute check-in deadline. (unless DPS has airside transit counters ?)

My Options from Singapore are

8:40pm SIN -> 11:30pm DPS (Air Asia) leaving 1 hour 40 minutes to transit
6:05pm SIN -> 8:50pm DPS (SilkAir) leaving 4 hours 20 minutes to transit
5:35pm SIN -> 8:15pm DPS (KLM) leaving 4 hours 55 minutes to transit (would fly business class on this option, if that makes a diference)

So my real question is 1 hour 40 minutes to short to transit or should I take the longer 4 hours 20 minutes option?