wood2-
if you know the vaccination history of the calves is up to date, o.k. if not, i'd give them a round of shots. 7-way, blackleg W/homopholus somnus, IBR/PI3, pour on for worms & int/ext parasites, and would also give a shot for pasturella.
for 750-800 lb. angus or angusX calves, you could expect to feed a minimum of 3000 lbs. of corn based feed to get them to finished condition, along with free choice hay (depending on your feed ration).
Corn and soybean meal is a pretty simple ration, starting out at about 14% protein level and decreasing protein as you increase feed level. you could start out with about 8lbs/hd/day and work up to 16 lbs./hd/day in about 2 wks. time. once they're eating about 2% their body wt. you will want to have their protein level back to about 11%, and they should be pretty close to full feed condition. after this time, increase feed level just enough that they can't quite clean it all up - over a 24 hr. period. from this point on, monitor their feed intake - keeping just enough in front of them to maintain full feed condition. the free choice hay could/should be a low quality roughage. don't need the alfalfa when fed in this manner. this method will likely take more than 3000 lbs. of feed/hd. to properly finish.
another option is to bring the calves up to full feed on corn and purina impact 44 with free choice low quality hay. at full feed the calves should again be eating close to 16 lbs./hd/day. then take away the hay and let 'em eat all the ration they want. simple, easy, and they won't eat quite so much. when they are near finished condition, they won't eat more than 22-24 lbs/hd/day. whereas in the first option above they will be eating well over 30 lbs./hd/day + the hay.
there are a lot of other ways to feed an animal but these two ways are easy and will work well.
in your post you mentioned taking them up to around 1000 lbs. small framed heifers will sometimes finish out near 1000 lbs., but typical angus, angusX steers will more likely weigh up 1300 lbs or more. there is a lot of good info on this forum which describes what a properly finished animal should look like. good luck.
ROB