I start with a paste comprising: Pigment, Isopropyl acetate, Ethanol,
Nitrocellulose resin and Isopropinol.
I convert this paste to a runny viscosity using acetone then add a
plasticisor after which I add Methyl Amyl Keytone to slow it down and
make it workable in creating a beautiful durable waterproof film on
anything I wish to put it on.
Great! Except it stinks and causes headaches.

My question is this, what safer alternatives are there for what I see
as my options,
Option 1 replace acetone with something slower. (Such as?) And
dispense with MAK.
Option 2 substitute something safer for MAK.
Option 3……4…..?

Hi ureka! My credentials: 45 years in the paint industry, 30 of which
as a paint chemist. First,if you experience headaches, do you have
adequate ventilation? Very important indoors. Open a window, set up a
large fan exhausting outdoors. 2nd: ALL organic solvents are toxic,
differing only in degree. But don't be alarmed, just be careful. (I
have inhaled more solvent in a week on the job than most persons will
in a lifetime...I am 75 years old and in good health.) 3rd, MAK is
odorous. You might try butyl cellosolve, which is slow evaporating and
more pleasant smelling. You can order this from Chemistry Store onlne.
4th, acetone is one of the least toxic solvents but very fast
evaporating. It is a good choice for you as long as you can slow down
the system with another solvent, such as BC mentioned above. 5th,
citrate based solvents are available in craft stores such as Michaels.
I have no experience with citrate solvents but they have a pleasant
odor. They may not have the solvent power needed in your system, but
are worth a try. 6th, these solvents, especially acetone, are
flammable. I would hope you don't smoke while working and that you
take proper precautions. Last, if you live in a house, DO NOT store
any solvent in the basement. Keep all solvents in smallest containers
practical and store in a closet or similar area.
   Hope this helps.
Knowitall22