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

Let's not even go into the paradigm shift that this development implies. The growth of a bitcoin futures market positions it even more as a commodity than a currency (in the US, the Commodity Futures Trading Commission regulates futures markets). And even more as an investment asset than a technology that has the potential to change the plumbing of finance.
The promoters of these products promise traders a way to beat the market by arbitraging prices between different exchanges. Don’t believe the hype. Bitcoin exchanges often have expensive withdrawal processes and hefty fees for trading bitcoin with fiat currencies, such as dollars or euros. Also, settlement of bitcoin trades can take hours. These factors will eliminate any profits from bitcoin arbitrage and may even lead to losses.
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“Bitcoin Improvement Proposals”, or “BIPs.” If accepted by a sufficient number of miners, BIPs may result in substantial changes to the Bitcoin Network, including changes that result in “forks.” Such changes may influence the price of Bitcoin and Bitcoin Futures Contracts. In particular, it is possible that the price of the Bitcoin Futures Contracts subsequent to a “fork” may be linked to the price of bitcoin on only one of the resulting Bitcoin Networks, rather than the aggregate price of bitcoin on all resulting Bitcoin Networks. The CBOE Futures Exchange (“CFE”) and Chicago Mercantile Exchange (“CME”) have announced different protocols for addressing forks.
A key attribute of a futures market is how its contract’s prices vary by expiration date. The succession of futures prices over time is called the “term structure”. If supply is stable (no seasonality or shortages) then typically futures prices will increase with expirations further in the future. This term structure configuration is called “contango” and it accounts for the fact that carry costs (e.g., time value of money) and profit expectations increase with time. Unless there are big changes in interest rates or the way that Bitcoin exchanges work I expect the level of contango in the Bitcoin futures term structure to be small. Bitcoins don’t cost much to hodl (once you have your hardware wallet) and there’s no apparent seasonality. The chart below from VIX Central shows a typical Bitcoin term structure (click on chart to get current data):
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Since the introduction of futures, the price of bitcoin has gone up, suggesting that there were more As -- people who wanted to be long bitcoin synthetically -- than Cs -- people who wanted to be short synthetically -- though again it is still early. Crudely speaking, the arbitrage spread suggests that there are also more As than Bs: There are a lot of people who want to be long bitcoin without owning bitcoin, but not so many people who want to own bitcoin without being long bitcoin. (Which makes sense! If you bought a bitcoin and sold a futures contract when Cboe launched its futures last week, you could have locked in a risk-free arbitrage profit of something like $1,200. But if you had just bought a bitcoin, you'd be up about $3,000 by now.) The costs of trading actual bitcoins on bitcoin exchanges -- in terms of blockchain transaction costs, exchange withdrawal limits, etc. -- are significant enough that people who want bitcoin exposure are willing to pay about 2 percent to avoid them.
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By now you may ask yourself, “If I think that the price of an asset is going to rise, why should I buy a call option and not the asset itself?” The answer is this: Options give you leverage. That means that with a limited amount of capital, you can profit much more by buying options than assets – but also lose much more. This is because a small difference in the price of the underlying asset immediately leads to a substantial change in the price of the derivative. For example, when pork belly prices rise from 1,000 USD to 1,100 USD (an increase of 10%), call options for 1,000 USD suddenly become much more valuable – their prices may rise from 10.5 USD to 105 USD. Thus, if you have invested all of your capital in pork bellies, you will win 10% – if you have invested in pork belly call options, you will pocket a 1,000% profit.