I had bought the gridseed to prevent the wallet from going out of sync because the current pools don't seem to be mining empty blocks. Since it only runs at 7 or 8 watts I will try to keep it running most of the time.
Its not the empty blocks, its the market-price/diff/reward ratio. At a diff of ~0.9 your 250kh/s need ~4hrs to pop a block when the chain is stuck. In StableCoin the block target is 40s and the diff adjusts every 90 blocks. That is after 90 blocks with a diff of ~0.9 have been mined slower than 40s per block in average, diff will decrease to reach its target with the hash it sees. So expect a good drop in diff once the 90 blocks are over (and expect a lot of multipools to join for the next 90 low-diff blocks)
Now once the diff falls a bit, the above equation of market-price/diff/reward gives a better result (which you also can trigger by giving insanely high fees, that has the same effect on the mentioned ratio as a diff that is lower or a higher market-price). At this time multipools monitoring SBC join in and harvest a few cheap blocks (difficulty-wise cheap) with much more hash than the current diff is adjusted for. This again blows up diff and now the chain is again stuck for 90 blocks
With what you do, you actually keep the chain moving, but it is a very ungrateful task for you, as whenever you worked diff down to a level that you could mine a few blocks with your gear, others come in stealing your fruity blocks.
Adjusting diff only every x blocks is fine for chains/coins with a very high and stable hashrate (i.e. BTC or LTC). For smaller chains, I believe that it is a much better strategy to adjust diff on every or every few blocks.
