For me anecdotally it works however there is no real tangible proof that it does work, everything is done on their end and you really can't verify anything.
You're wrong. You can verify if they did mine the block that had your transaction in it by simply checking the transaction ID > Block/ Included In Blocks (it differs depending on which explorer you use), click the block number > check the part where it says "Mined By" or "Relayed By".
All I can say is that definitely have to get in before 20 minutes after the start of an hour otherwise you're not gonig to get a spot on their accelerator.
1 minute before the hour reset is more than enough.
I have tried viabtc to accelerate my transactions but all the times I got error message of over flow or something similar to that. Do we need to watch and wait till they will mine a block so that they will start accepting new transactions to accelerate to be included in their next block to be mined by them.
I've never had any issues with their services, as long as you attempt to accelerate on first few minutes of the hour reset (which is 1:00, 2:00, 3:00 and so on, by default forum time).
Transaction went trough with only 5K satoshi fee within 40 minutes.
466096 block was indeed mined by ViaBTC
That's perfectly normal since it falls above the minimum fee of 0.0001BTC/KB ratio.
0.0001 BTC/KB -
Acceptable0.00005 BTC/500 bytes -
Acceptable0.000025 BTC/250 bytes -
Acceptable