I don't know the process of how Tony used his products.
when I first started using Epifanes, many years ago, I called the
local distributor about thinning and the guy said 100% mineral spirits
will work fine. after that project, I ordered their proprietary thinner
for spraying (also used in brushing).
I am not a chemist by any means. but, when I smelled the "special spray thinner"
it smells exactly like VM&P Naphtha - not mineral spirits.
so whatever you can find will work well for thinning.
for me, I thin way, way down to water consistency and build up layers
with decreasing thinner and a couple of unthinned layers.
anywhere from 8 to 15 coats will be required for the best UV protection
and recoated every couple of years, depending on the exposure.
ALL clear coats are maintenance items. you must be willing to put in the time
when required to maintain the finish. if not, you will be better off using paint.
this information was copied from the WWW.
"Mineral spirits will dissolve only paint that is still fresh.
Naphtha is a petroleum solvent similar to mineral spirits but with a greater volatility;
it is used chiefly as a paint thinner or a cleaning agent. Naphtha is a more powerful solvent than
mineral spirits, so less is needed to thin the same amount of paint. But it also makes paint dry faster
and may make it hard to blend strokes or brush out drips.
Naphtha is highly flammable; when using it, work in a well-ventilated area -- out-of-doors,
if possible -- and wear rubber gloves and a respiratory mask. It can quickly dissolve wax layers,
but naphtha can also penetrate through the wax and seep under veneer.
There, it will dissolve the glue, causing the veneer to loosen".
so ~ the bottom line is:
100% Mineral Spirits for brushing
or their "special brushing thinner" TPVB.500
which is probably just mineral spirits.
VM&P Naphtha for spraying (unless you have veneer to deal with).