Long course training sets - 200 strokes and 200/400 IM

Hi there. I'm looking for some effective long course training sets for the 200 strokes and 200/400 IM. I already train with a masters team, but I'm looking to do 1-2 sessions a week on my own. I want to make these sessions very specific with the goal being to race faster. I want to improve 2 things: 1. Speed - improve my splits, so my overall times go down 2. Endurance - ability to 'hang on' for longer Any suggestions would be appreciated. Thank you.