When to Switch?

I have been using a mixture of the greyskull LP and stronglifts 5x5 but learned of Sheiko about a month ago and I have been wrapping up my training cycle to begin there.

My question is, when is it okay for a novice lifter to switch to sheiko? I would say I might be entering the intermediate territory but absolutely nowhere close to advanced and I want to make sure I pick the correct program that my body can actually handle.

I know Sheiko has some "lighter" programs, which ones should I be taking a look at primarily for my scenario? My friend also referred me to several "undulating" program but I'm not sure what exactly he means. He referred to it as "DUP".

Thanks in advance!

If you buy the app you have the beginner program and the 'intermediate' 3 day cycle. Read this http://sheiko-program.ru/forum/index.php?topic=3.0 topic to get a starting point for more information read the sticky's