pin it out with professional insect pins.
position as wanted, and then after a day of drying out, spray really well with non aerosol hairspray..maybe recoat every four months.
thats what i have done and they are perfect and have lasted many years.
ive done that with any and all spider,solfugid,scorpion, and scolopendre mounts skins and specimens.
perfect results every time.