I won't answer other questions since the answers are similar to what "aTriz" stated.
3. Do you use free accelerator to save money on mining fee?
I used to do it once a month, for clearing my "Unspent Outputs" but due to recent events, it's no longer possible.
For Viabtc, it only accepts submissions every hour, and being a user of it, the 100 submissions are all done within every first minute of every hour. If you can consistently push through a transaction on the first min of every hour, then sure, cheap out on fees.
I would like to point out that ViaBTC's free accelerator no longer works (
see my post here), you can test the method I mentioned there as well, however their "Paid service" is something I advice in comparison to other paid accelerators (cheaper option):
https://vgy.me/keyab4.jpg (had to avail this since the exchange that I used, sent a very low transaction fee and it was urgent)
ChipMixer, are you planning to introduce a similar service (an actual one)?
