Probably best to just randomly work on extra pieces after a release similar to what InArt did with the Ledger detonator, with your customer base none the wiser until you catch them up to speed.
Creating accessory packs with your customers privy, for every figure you release is a sure fire way into bankruptcy.
You don’t want your customers to think “I’ll wait on the 2.0, or I’ll wait for the cheaper accessory pack”. You want to sell them a complete figure showing the craftsmanship that went into it. A random Pfieffer head down the line is better than actively planning an accessory pack that will not be included in the PO of your figure.