since it didn't take too long I then ran three P+1 curves at
B1=100000000
B2=10000000000
The difference in time by increasing bounds by 10X, Stage 1 10x longer stage2 4x longer.
1 curve of stage1 with B1=B2=10000000000 would take about 2.5 days on my 2.2G barton system. And you can contiune stage two from the stage1 save file but each stage 1 started with a different x0= as you will note.