Other forms of swap agreements that the Funds may enter into include: interest rate caps, under which, in return for a premium, one party agrees to make payments to the other to the extent that interest rates exceed a specified rate, or “cap”; interest rate floors, under which, in return for a premium, one party agrees to make payments to the other to the extent that interest rates fall below a specified level, or “floor”; and interest rate collars, under which a party sells a cap and purchases a floor or vice versa in an attempt to protect itself against interest rate movements exceeding given minimum or maximum levels.
The value of such Creation Unit for the S&P 500 Dividend Aristocrats ETF, the MSCI EAFE Dividend Growers ETF, the DJ Brookfield Global Infrastructure ETF, the Global Listed Private Equity ETF, the Large Cap Core Plus, the Hedge Replication ETF, the Merger ETF, the Inflation Expectations ETF, the CDS Short North American HY Credit ETF, the UltraPro Short Financial Select Sector ETF, the UltraShort FTSE Europe ETF, the UltraPro Financial Select Sector ETF, and the Ultra High Yield ETF as of each such Fund’s inception was $2,000,000.
Decentralized cryptocurrency is produced by the entire cryptocurrency system collectively, at a rate which is defined when the system is created and which is publicly known. In centralized banking and economic systems such as the Federal Reserve System, corporate boards or governments control the supply of currency by printing units of fiat money or demanding additions to digital banking ledgers. In case of decentralized cryptocurrency, companies or governments cannot produce new units, and have not so far provided backing for other firms, banks or corporate entities which hold asset value measured in it. The underlying technical system upon which decentralized cryptocurrencies are based was created by the group or individual known as Satoshi Nakamoto.[28]
I have worked with the CME in the past on product development (specifically CDS futures) and from my experience, they would not have missed anything this simple.  In fact, while I am not a huge fan of the concept of Bitcoin futures, as currently implemented, I do not expect any errors in the operation of the CME or CBOE futures contract.  I am sure that regulators will be questioning them on the back of the OKEX, as they should, and I am also quite positive the exchanges here will pass with flying colors.
Start small. Get familiar with the platform you're using before you make any significant trades. BitMEX offers a sandbox using Testnet coins. OKCoin and BitVC do not offer a demo version, but you can start small with 1 contract and test how Open Long, Open Short, Close Long, Close Short and different order types work. If you contact CryptoFacilities you can also get access to a demo platform to use.
Currently there are a several digital asset trading platforms that provide investors with forms of derivative products such as futures, so one could estimate and synthesize the discrete futures curve from the averages of various curves. MVIS research used BitMEX, OKCoin, CryptoFacilities, and BTCC as sources, to construct and approximate bitcoin futures curve based on non-U.S. bitcoin futures trading on these exchanges.

Since you bought 68.4246 BTC, you want to short 68 BTC and lock in the USD value. You will have 0.4246 BTC left over, which will give you a slightly long bias. You can either fix this by only buying 68 BTC in step 1 or by giving yourself more short exposure by shorting 69 BTC. Remember that CryptoFacilities contracts are inverse (which allow locking in USD) and are denominated in BTC