Here‘s the deal with that. If you lose 16 pounds of spring load and your valve train goes out of control you should probably look at lighter valves, lighter retainers, bigger stiffer pushrods…stuff like that.
That is the worst issue with any FT cam. You can’t add spring load to get rpm. So you have to make other parts lighter and/or stiffer.
Im all for shimming them as I said above, but not because I’d be worried about 16 pounds (if they lose that much) but because I get mental over things like that (lol it sounds like you may be of the same mentality lol) so you have to make yourself happy.
And if that means shimming them back up, I wouldn’t waste another second thinking about it, I’d just do it.
My less than .02 worth of opinion.