How diverse is your product base? -- if not very diverse then having a few extra products might not cause very much financial harm.
Do you have a way of tracking if someone is a repeat customer (also are your customers' identities verified)? -- If so, then you can assign each customer a risk profile based on their prior behavior. For example, a customer who has ordered from you multiple times and that has not ever had any kind of failed payment/deposit will probably have a higher chance of having their transaction confirm (or a transaction in the appropriate amount) than a customer who has a history of failed payments/deposits. Also if you have done business with someone many times in the past (and earned profit from this person), then the risk of someone trying to cause you financial harm would be low.
What you are describing sounds very similar to how Gemini will
pre-credit some Bitcoin deposits for trading nearly immidiately after receiving the transaction. If this is something similar to what you are trying to implement (or improve), then you can look at the total value of the account verses the value of the deposit. If the deposit is under a certain percentage of the account's balance, then the amount under the certain percentage threshold might be able to be excluded from the total credit risk.
