In my opinion best way to learn is going all in. Forces you to learn quickly. I've only used a DE once or twice and can't say if the straight takes much longer but I imagine it may. For me though, I can get a very close BBS shave in 2 passes with a straight and it takes me about 10-15 minutes. That includes lather building, stropping and cleanup so it may be possible that you may find the straight will work into your regular schedule.