Balance unit strength

We have replaced glass units in 6 existing windows with units built with laminated glass. The windows are Silverline 2900 series SH and the existing balance units are designated 30-3, 18-5, and 24-5. To handle the additional sash weight Silverline has recommended: 30-5, 18-7, and 24-7. Their 3 week delivery is too long. Can you quote an equivalant unit with delivery prior to Sept 2nd? We need 2 ea. of the 3 sizes. Closest unit I see in your website is a 795 series. But I cannot decipher how to specify balance strength. Rick, Gainesville Windows & More