Blackie, I understand that your Main list is designed to shoot at straights, but in this case I might think about adding some coverage on the combos of 518. I found some interesting history for the 815 combo of your 518. I did this chart as part of my analysis so I thought I'd post it up.
04/10/20,036,071 | 12/17/12,865,337 | 09/05/01,870,958 | 02/12/01,720,545 | 09/12/97,452,019 -
04/11/20,992,865 | 12/18/12,802,352 | 09/06/01,865,790 | 02/13/01,217,190 | 09/13/97,900,865 ---
04/12/20,730,394 | 12/19/12,170,265 | 09/07/01,680,567 | 02/14/01,837,865 | 09/15/97,090,707 -
04/13/20,115,258 | 12/20/12,089,255 | 09/08/01,137,948 | 02/15/01,435,109 | 09/16/97,203,500
04/14/20,516,154 | 12/21/12,854,649 | 09/10/01,002,807 | 02/16/01,771,892 | 09/17/97,228,911
04/15/20,769,050 | 12/22/12,227,759 | 09/11/01,255,230 | 02/17/01,217,652 | 09/18/97,256,845
04/16/20,265,085 | 12/23/12,242,344 | 09/12/01,750,279 | 02/19/01,670,622 | 09/19/97,542,821
04/17/20,557,075 | 12/24/12,870,425 | 09/13/01,163,070 | 02/20/01,495,755 | 09/20/97,072,366
04/18/20,613,917 | 12/25/12,749,219 | 09/14/01,076,769 | 02/21/01,612,014 | 09/22/97,159,488
04/19/20,127,495 | 12/26/12,684,518 | 09/15/01,594,937 | 02/22/01,685,648 | 09/23/97,959,050
04/20/20,600,433 | 12/27/12,333,837 | 09/17/01,273,287 | 02/23/01,900,283 | 09/24/97,232,344
04/21/20,097,855 | 12/28/12,670,639 | 09/18/01,831,502 | 02/24/01,505,041 | 09/25/97,159,123
04/22/20,142,896 | 12/29/12,471,404 | 09/19/01,353,388 | 02/26/01,376,018 | 09/26/97,654,656
04/23/20,227,087 | 12/30/12,333,427 | 09/20/01,173,376 | 02/27/01,712,213 | 09/27/97,651,034
04/24/20,246,028 | 12/31/12,549,489 | 09/21/01,428,825 | 02/28/01,561,201 | 09/29/97,189,509
04/25/20,032,851 | 01/01/13,332,377 | 09/22/01,129,737 | 03/01/01,938,944 | 09/30/97,767,800
04/26/20,244,016 | 01/02/13,428,218 | 09/24/01,797,814 | 03/02/01,707,897 | 10/01/97,653,431
04/27/20,267,426 | 01/03/13,136,516 | 09/25/01,346,644 | 03/03/01,760,520 | 10/02/97,299,238
04/28/20,806,186 | 01/04/13,468,739 | 09/26/01,370,485 | 03/05/01,763,553 | 10/03/97,947,658
04/29/20,012,711 | 01/05/13,502,184 | 09/27/01,952,151 | 03/06/01,957,551 | 10/04/97,992,394
04/30/20,384,043 | 01/06/13,881,113 | 09/28/01,730,395 | 03/07/01,136,992 | 10/06/97,569,640
05/01/20,524,372 | 01/07/13,462,235 | 09/29/01,532,554 | 03/08/01,469,399 | 10/07/97,918,612
05/02/20,949,938 | 01/08/13,027,941 | 10/01/01,473,172 | 03/09/01,722,636 | 10/08/97,135,348
05/03/20,710,621 | 01/09/13,882,077 | 10/02/01,660,312 | 03/10/01,488,686 | 10/09/97,230,456
05/04/20,452,313 | 01/10/13,064,614 | 10/03/01,234,995 | 03/12/01,864,776 | 10/10/97,896,868
05/05/20,???,??? | 01/11/13,815,494 | 10/04/01,060,815 | 03/13/01,958,815 | 10/11/97,344,815
815 really likes to follow 865 at a distance. Honestly, I'm not certain how I'm going to lay this, but I'm in one way or another.
Good Luck!!!