Hmmm... Kickstarter experimented with a "no-go al" campaign option for a time, but it appears that has since disappeared from their platform. So I see a couple ways to do it.
If you wanted to stick with kickstarter, just run a second campaign with a very low goal. Make it clear in the risks section that the previous campaign covered the baseline cost of RND and Tooling, and that this campaign is simply to increase order volume, and is therfore very low risk.
Alternatively, since Kickstarter takes quite the cut of your funding, and you already have the word of mouth and visibility from your first successful campaign, you could move away from kickstarter.
Less popular platforms like Indiegogo take a smaller cut, but are less reputable (I've backed nearly a hundred kickstarter campaigns and none on Indiegogo. All the Indiegogo campaigns I considered backing fell through or came out with major deficiencies).
You could also take pre orders yourselves directly. Set up some sort of e-commerce on your website. Paypal is an option. Many web design companies (e.g. squarespace or wix) have built in e-commerce options. You really just need any method of getting money in advance for the product, to cover your huge first round manufacturing costs.
Regardless, as pointed out by first round backers, make sure the "slacker" discount isn't as good as the first kickstarter discount was. And make it clear we're second tier on the delivery timeline.
The one complicated bit would be: you want to take more pre-orders to increase your manufacturing piece counts to reduce per piece costs. But a larger piece count order will likely take longer to fulfil. So you do run the risk of pushing back the delivery date for your kickstarter backers by taking additional orders. You'd have to talk to your manufacturer about how much impact to expect. As a backer of many many kickstarter campaigns, I would find this acceptable. We back campaigns to support designers in getting off the ground. A small delay to allow you to get a stronger start is par for the course. But many backers don't understand the platform as such, and view it as a straight product purchase (a problem I could see you've experienced both sides of in your VAT FAQ). If there will be manufacturing delays, be very transparent with your first round backers on that front.
Good luck!
