I am saving some of this (at least, the "how to's") for a tutorial I hope to put together sometime around mid-December. But I'll give you a foretaste...
For one, this finish is really only handy for folks who finish a dozen or more wood pens at a time. For those of us who do onesies and twosies, a CA finish or dipped/wiped lacquer finish is likely the best bet (though most all of you would benefit by upgrading to a precat lacquer, read below, it will work just like Deft).
This all comes 100% from my experience as a cabinet maker. There are basically three types of finish a cabinet shop will spray, and all three are very useable for us. They go from least durable to most durable (there are other finishes out there such as 2-part polyurethane finishes I won't discuss b/c are not very commonly used due to high cost or other weirdities).
The three main types of finish:
1) Regular lacquer (ie, Deft). Easy to use. Yellows in time b/c it is nitrocellulose based. Usually around 25% solids content (meaning you are buying 75% lacquer thinner). Not very durable compared to it's bigger brothers-- the main problem is chemical durability, it simply isn't very resistant to alcohol and cleaners. On a pen, hand crud is about the worst a pen is likely to see, so it works fine. I, however, prefer something that is more rock-solid.
2) Precat lacquer. The same as above, but it comes with a catalyst already added to it, and most all of them also have a good bit higher solids content (some are around 35%). A LOT more durable than regular lacquer, cures harder, and cures to a useable hardness much quicker (two days if you want to buff and assemble). Much more chemically resistant. Does also yellow with time, but that isn't a concern for the vast majority of woods since they are already dark or yellowish.
3) Conversion varnish. Often approaching 40% solids (ie, it cost more but you get more stuff for the dollar). Contains NO catalyst until YOU add it and it has an 8 hour "pot life" once catalyzed. CV is basically a type of catalyzed lacquer. The big difference between cv and lacquer is the catalyst and the type of solids. CV is usually a polyester and/or melamine resin concoction and is generally 100% non-yellowing. It will "dry" a touch quicker than lacquer, harden to a buff-friendly hardness overnight, and if you don't really want to buff it, you can assemble the pen just a few hours after spraying.
CV is only available from places that sell finishes to cabinet shops. You usually don't need a commercial account, however. Understand that it is designed for use in "industrial" woodworking, which IMO many of us qualify so long as we take precautions. CV is a solvent-based finish, and you MUST have good ventilation and wear a mask if you are spraying much.
I wish I had time to give you more info, but can't due to time constraints.
If, by the way, you own a general woodshop or cabinet shop or a very active penshop that will benefit from using this kind of product, I'd encourage you to check out www.mlcampbell.com and browse. This is the company I use for most of my finishing needs, find a distributor and see if they will send out a rep to demo their product. Just know that they cater mostly to cabinet/furniture shops, so they may not be able to send someone out to demo in a pen shop, most of their reps will have never even seen a wood pen (but, may become a customer if you have a couple freebies for them!).