They are boring and usualy you should make profit out of them. Problem is bad luck. At 1-2 dollars buy-in +rake you have to win 2 out of 3 to make profit. The problem is that if you have bad luck several times you will have to work a lot to make up for the lost money.
The single problem i see is the rake at smaller buy-ins.
80% of the time when the blinds are 100/200 at shorthanded DONs there are only 4 persons remained and if you play correct untill that time you will have at least 6-7 BB and the only thing remaining is to chose the moment to push.
15% of the time at smaller buy-ins you can get ITM without playing a hand cose the donks knock each other out.
Holdem manager can help you a lot especially for the high blind play , because you will have to chose the tight players to bully.
I myself 90% of the time i do not play a single hand untill the blinds are 50/100. Only play AA, KK, AKs, and ocasionally limp with small pocket pairs to get a set.
Than when the blinds are high just survive with the same stack untill someone gets knocked out and someone will eventually because players do not have patience.
Longest game of this type that i saw at shorthanded lower buy-ins DONs was 20-25 minutes.
U can play 4 table at once but i would not suggest to a beginner to play more than 2 at a time and also i would suggest to register at the second one when the blinds are 30-60 at the first one , just because you will not want to make 2 tough decisions at 2 table at once when the clock is ticking.One mistake and you lost meaning that you will have to win the next 2 to make up for the lost money.
Anyway if you are a decent player i would suggest you to play the normal SNGs at lower buy-ins. Players are not that patient and most of the time you will find yourself in the bubble when the blinds are 50-100 and that time if you have good knoledge of the high blind play you will win the tournament if you do not have bad luck. The ROI can go from 30% to 60% easy.