Not to toot my own horn, but for designing Janus' projects I used a document where I listed Janus' lab totals on a line below the design calculation of level. The pain however is when the umpteenth effect is so difficult that you decide the magus spends a few years of study, you need to go back and correct all the numbers. Which I'm sure never happened, so the lab total line for Janus is a hint at best. 