In your situation you have the opportunity to really shape your herd from the word go, a luxury very few of us has had. You begin with enough numbers to apply selection pressure right from the start, done correctly it will set you up for the future.
I assume they are all bred in a given breeding season so they'll calf within 60 days of each other and that you have a calving season in mind that will suit your management and conditions?
Before anyone can even begin giving advice on bulls for the future I need to see the heifers. There is a lot of variety in the breed and some extremes of this variety needs to be get rid of or atleast addressed in the correct way.
For expansion purposes, only keep heifers out of cows that weaned calves in the top 75% of the calfcrop (usually I'd say only the top 50%, but since you're right in the beginning stages I'll be leanient) and most importantly only out of dams that are confirmed to be bred back. Any dams that are in poor condition that are bred back can be kept another year to generate income, but i wouldn't keep their heifer calves as replacements, especially since you haven't made the bull selection to fit your needs.
There is no point in retaining heifers that weaned light or whose dams couldn't raise a calf and breed back or maintain themselves to the point where they might need special care to survive the winter. All those types will cost you money and work in the future, rather get rid of those now or atleast not knowingly take their problems to the future.
Weigh all calves shortly after birth, this will prove handy information for future bull selections.
As far as bull selection, I'd synchronise and AI to a few bulls to adress issues the cow might have, not neccesarily expensive AI sires, just good solid bulls. If you like I can make individual suggestions if I see the heifers. Buy a decent young black angus bull if you can't find a good affordable hereford bull as a cleanup sire and do as Frankie suggested, sell the baldie calves for a premium, especially the heifers should be in good demand.
Keep your breeding season short right from the beginning culling ALL opens, pay attention to pigment and eyeset from the beginning, plan your health program well in advance of the breeding season and consult your vet, some vaccines might affect conception rates especially in a synchronised AI program.