Selecting Pacelines: How Do You Do It? Good list.
I like to find 2 lines, to make I'm not using abberant lines.
I want to to use lines that will show what the horse will do when at the right distance, surface, and class level. So I am not afraid to use lines #7 and #10 if that's what it takes. I am looking at pace ability, nothing else. Class, form, trainer intent can be evaluated using recent races, works, riders, etc.
Howard Sartin used to stress, don't put horses in the computer that you think can't win, and if you think a horse can win, don't use a line that won't let him.
One thing I watch out for are extreme paced races. BRIS has race shapes listed, and I am hesitent to use races where the race shapes are beyond +6 or -6. That is +/- 3/5s of a second. Steve Davidowitz once did a study that suggest that range was more realistic than Quirrin's +/- 1/5, and my own research when I was using HTR gave the same results.
If today's race has more than one horse likely to run extreme early, I will use those extreme lines.
Another thing I look for is riders. If the rider who last won or finished close on the horse, I may go backand use a line where he/she was on.
Of course, we have to take what the PPs give us. Sometimes we can't find ideal lines and have to use what there is. Or pass.
There are a lot of races every day, and there is another one coming up in 5 minutes.