I am removing a baseboard in my home and am going to cut and cap the pipes under the house in order to make this happen, then re-solder the pipes. How close should I cut off the pipe to the main water circulating pipe when I do this? Once I'm done, approximately how many times would you guess I'll need to bleed air out of each baseboard? THanks:)

Cut them where you can resolder them without burning the house down. You might have to bleed a few times to remove all the air.