995-16 valve spring alternatives

When I build my motor I had intended to use my 273 rockers. As most know my 273 pushrods are too long so I been running some sloppy stamped rockers. Got a push rod checker tool in the mail. Gonna order springs and pushrods in one order. My cam is a comp thumper cam. .235in .249exh @50 .494in .483exh 107 lsa 2200-6100rpm range. Now onto my question, comp cam's recommends their 995-16 DUAL SPRINGS. My heads are not machined for dual springs and I do not want to pull heads to machine them.

What is another single spring that will work with my cam/rpm range?