Been where you are, and as Ken says, getting a crop of calves on the ground will be the biggest priority...That said, you also have until next June before you need a bull at the earliest. You could always get this bull calf, and then still keep your eyes open. You might find a bull that someone else is "trading off" because he has used him for 2 or 3 years and has daughters, or something like that. One thing, what color calves sell the best in your area? That should have some impact on what color bull you get. With the market being down, having the "desired" color will add a few pennies to the price and we can use every single extra penny we can get. Also. you didn't say how many cows you have for him to breed??? I am assuming this bull is a spring 2016 calf, so he will only be 15-16 months when your cows are calving. You don't want to overdo it (too many cows)with him the first time breeding.
Yes you should keep him separate from the cows when they start calving and then put him in when they are about 30 days fresh so that you get a uniform age group of calves which will give you more of an opportunity to sell them in groups instead of singles. I wouln't let him breed the early cow right back but keep him out til there is a group to breed. Since the majority aren't calving til June, I would think you might want to get the next calves out a bit sooner so I'd put him in late July to try to back the calving dates up to May instead of june.