There are three general approaches to tempering:
As you state you want a machine, I am going to focus on batch and continuous methods.
With batch tempering machines, a specific quantity of chocolate is brought into temper and once that chocolate is used, a new batch needs to be brought into temper. The key advantage of this approach is that the machines can be very cheap. The key disadvantages of this approach are a) it is slow and b) mold cavities need to be filled individually by hand or by the flood and scrape method.
With continuous tempering machines the chocolate in the working bowl is out of temper. It is tempered in a pipe that is kept at a specific temperature and any chocolate that is not used returns to the working bowl where it is melted out of temper before before going back through the tempering pipe. The key advantages of this approach are a) you can add chocolate to the working bowl as you fill molds so you can temper a lot of chocolate without having to stop and b) by interrupting the flow of chocolate you can fill mold cavities with a specific amount of chocolate. The key disadvantage of continuous tempering machines – in the scenario you present – is that there are none available in the low-thousands (under 5) of $€£.
I do applaud your decision to go with multiple machines compared with trying to do everything in one machine as labor is a major aspect of the cost of producing bars. It makes sense, in the long run, to get more machines (especially if you can finance them) than to try to do everything in one machine and spend a lot of time in cleaning/changeover – a task you will come to hate if you have to do it regularly.
However, individually filling molds with a specific weight of chocolate is arguably just as frustrating.
If the goal is 1000 bars/week across three types of chocolate, it would be my first instinct to get a small continuous machine for the dark and milk bars and a batch machine for the white bars. Unless your are advertising "dairy-free" bars, it's not all that time consuming to go back and forth between dark and milk on the same machine. In most cases dark and milk make up the bulk of production and the comparatively small quantity of bars that are white chocolate can be done in a batch tempering machine.
You also need to consider sales growth into your plans, buying not only what you need for today but for tomorrow and to meet peak demand.
It's also fair to say the scheduling production is key to getting the work done. With a continuous tempering machine you could do all the dark one morning (say Monday) and the milk on Wednesday. White bar production could happen in the afternoons of those days, with wrapping on Tuesday and Thursday. Of course, that's a purely hypothetical scenario but it gives you an idea of how production scheduling can help you meet your target throughput requirements.
If this helps, let me know and I can perhaps offer some specific equipment suggestions.