TFS Head question

I was reading about the twisted wedge heads, and looking at the differences between these two:

http://store.summitracing.com/default.asp?target=partdetail.asp&part=TFS-51400002&FROM=MG

http://store.summitracing.com/defau...t=TFS-51400004&autoview=sku&Ntk=KeywordSearch

The second one has upgraded springs (it uses a dual spring setup as opposed to single). I was reading this data sheet about the two heads:

http://static.summitracing.com/global/images/instructions/tfs-sbf_tw_sh.pdf

If I understood it right, the one with dual springs has a maximum lift of .600". Did I read that right? The reason I ask is because with the TFS Stage 1 Cam, exhaust lift with 1.7 rocker arms is .5418", which is too much for the single spring heads, but if I understood that sheet correctly, with the upgraded springs, .5418" would work fine. Thoughts?

BTW, I posted this on the 94/95 section also, but there's not many of us over there right now, and I need some info quick since I bid on some nice new TW heads (dual springs) on ebay ending tomorrow.

I know there's a lot more to cams than peak numbers, and I know the heads don't flow much past .500", I just need to know if it will work since I can get some 1.7's for cheap. Besides, I'm planning on getting these ported some, so they should flow a little better than even what that sheet says.