It sounds like your friends are on track with that style of drying....my advice is to ask them their technique.....it could take 2 or more yrs ADing. I AD my lumber than KD for the most stability.
I think you've jumped in as many others do WITHOUT doing your homework first. Your project is doable BUT has many risks and time involved. My opinion I'm fixing to give isn't because I sell wood BUT because most people DON'T have a clue of what's involved NOR what's the correct goal should be.
My advice to anyone starting out is to buy correctly dried wood first and then learn all aspects of drying prior to purchasing and drying....you'll find out it's cheaper when ALL the time and risks are figured in, to go ahead and pay the large bucks for a dried slab ready to use.
Risks from green wood....1) bugs to start with 2) warpage 3) discoloring 4) checking 5) splitting
Maple in this case discolors worse than say oak or cherry due to being a "white" wood and stains very easily in drying as you're noticing the color changing now.
My advice is to sticker and wieght it good at this point and wait to dry. If your not interested in getting a meter than your not very serious about being correctly done.
quote "Kiln drying sounds like quite an art, adding humidity to dry it with circulating heat so the outside doesn't try faster than the inside." ????? questionable info but some basic truths...it does get very technical IF you try to speed things up!!!
Best of luck drying.
Have a Blessed evening.
Tim