Approximately ten months since Skin Game. A quarter box. And Dresden split with Murphy. So 1/8 unless you believe Harry skimped her.
The problem here isn't money.
Where do you get a quarter of a box? It was half a bag of diamonds divided into five cash boxes. I have no idea how full the boxes were other than they were heavy and Marcone was impressed by it.
How much money do you think the diamonds will work out to be? I remember a thread from the long, long ago that had various estimates ranging from insanely high to comfortable retirement levels if invested wisely after the necessary spending spree of a father of one who has basically no tangible real or personal property. The only thread here I found had an estimate of about 11 million dollars for Harry's cut (and I can't find it now). He had Harry's share at something like 21,000 carats.
Here is a link to priscellie's estimate on reddit:
https://www.reddit.com/r/dresdenfiles/comments/273l6q/skin_game_spoilers_money/chxf3vf/. The estimates of Harry's share on that page are 11,000 to 17,009.7 carats.
The real problem is figuring out how much the diamonds are worth and what Harry can get for them. Is there a supernatural buyer who is willing to pay vanilla retail prices in bulk? Higher because of the radiation point made in the reddit thread? Is he going to have to fence them a little at a time like Valmont suggested to Charity? What percentage of retail will the fence pay for them? What quality and size are the diamonds?
I found a website that lists per carat prices for parcels of diamonds ranging in size from .002 to 2 carats with per carat price.
https://www.gndiamond.com/parcels/. The prices range from $295 to $3,580 per carat to with an average of $1,146 per carat. Based on the amount of carats predicted above and the wholesale prices on the website I found, Harry's take is anywhere from $3,245,000 to $75,180,000 with an average of $18,430,710. That's not taking into account any discounts if he is fencing them.
And none of this takes into account income and gift tax. The highest marginal income tax is 37% and was probably 39.6% when Harry got the diamonds ($118,118.75 plus 39.6% of the amount over $406,750 for 2014). The gift tax rate has been 40% the whole time. Gift tax is a little complicated, but basically, one can give away about $14,000 annually to any number of individuals before having to file something. In addition to that amount, one could only give away $5,340,000 before paying the gift tax in 2014. If Harry exhausts his gift tax exemption, i.e., he has to pay some gift tax, Harry's estate will have no exemption and will pay 40% in estate taxes (unless the exemption is higher when Harry dies). Now someone could donate any amount to a charity set up to help the victims of a disaster and get a tax deduction.
Furthermore, I don't know of anyway to front load all Maggie's SMAGT educational expenses without incurring gift tax consequences, let alone college. If Harry sets up an irrevocable trust for Maggie's education and dumps all the money she'll ever need (for education or otherwise) in it, there will be gift tax consequences.
The average annual boarding school tuition is $38,850. Of course, there are some schools with tuition as low as $10,000 and others as high as $60,000. Most boarding school tuition costs include room and board, but some don't.
http://www.collegebound.net/content/article/how-much-does-boarding-school-cost-/18833/