Amysdaddy, just an idea here but you may be able to seal your acrylic paints with Future
brand acrylic floor wax. You must test this first on scrap material. If I learned anything from general and organic chemistry, "like dissolves like." Future works extremely well with most modeling paints, but I don't know of compatability with water based acrylics. If this works ok with your test piece you can then dull it down by using dullcote lacquer. Also, I have clear coated over ben moore paints (water based acrylic) with clear dull lacquer and have had no problems. Hope this helps BT.