Please note I have never seen the nova
Well I'd take it to another bowshop and get a second opinion. The PSE website clearly states it has 20lbs of adjustment without a bowpress.
Unless the limbs have been changed from the original stock ones I'd say just screw in the limb bolts all the way and then back them out both equally until desired draw length has been achieved, But not more than 4 complete turns
Here is the website for reference http://www.pse-archery.com/prod.php?k=135541&u=0811SU
I'm also assuming you are talking about the Nova SU, because the PSE website has nothing on "Nova RF".
You may also want to consult your owners manual or call PSE up.
Hope that helps,
PSE Stinger, Mongoose arrow quiver, Top gun 3 pin sight, Whisker Biscuit arrow rest, Cobra 8 oz stabilizer, X weave 200 arrows, Tru-ball "stinger" release