IMHO, bitterness defines a pilsner along with the pilsen grain flavor. The total IBUs in a pils are less important than the actual bittering charge. Take @voodoo_donut 's pils recipe as an example. Total 38 IBU getting about 5 IBU from the late flavor/aroma charge and 33 from the 90 min bittering charge.
I like a bitter pils but I also like using yeast that focuses on the malt because i believe some of the bitterness or low level "astringency" for lack of a better word comes from the grain flavor, but I degress.
I generally bitter my bohemian pilsners to around 30 IBU with the 60 minute charge, 90 mins in Voodoo's case. I've brewed many pilsners with no other hops than the 60 minute bittering charge.
I find the late charge gives it a little of the spicy aroma of the noble hops I prefer in my pils, so generally do a 5 minute addition and don't really concern myself with the additional IBUs because they're not perceived as bitterness in the final beer.
Sorry for the long and circuitous route to answer your question with..."really doesn't matter it's probably personal taste". If you look at the BJCP guidelines for the style the sought after aroma is the grain and yeast aroma and hops are a minor contributor. "Hop aroma may range from very low to a medium, spicy or floral hop presence." Having said that if you want to take @sneezles61 approach of more is better like in an IPA, have at it and report back your results.