Ask the breeder whch type of bottle they ae using and then get the same make. I use Nettex non-vac bottles (500ml) and kids start off with 4 feeds per day, then after 3 months I educe by a feed per month and usually stay with one (late night) feed until I get fed up/run out of milkers in milk.
Depending on how many kids you are getting and what your budget is, there is a goat milk powder available (Caprilac from Goat Nutrition) but many people use Lamlac (or similar) mixing it thinner than it says on the packet.
If you can source fresh, raw goatsmilk (frozen maybe) at a reasonable price from a nearby goatkeeper that would be your best solution. Í take it these kids are already on the bottle - if they are still on their dam you will be struggling to get them onto the bottle at their age.