I prefer to not have any slop at all in the threads but not to the point of it being even slightly difficult to screw on by hand especialy so with a stainless steel barrel. I would also use a little anti sieze on the treads at least while working on the correct fit as it doesn't take very much for it to gall and lock up while doing so.

JLouis

Thread fit requires some clearance. 
The handy drill/tap charts that recommend a specific drill size for use with a specific tap size and thread pitch provide an established percentage of contact between the internal and external threads.
A higher than standard percentage of contact between the threads may eliminate undesirable slop, but too high a percentage of contact can lead to the above mentioned galling, and to seizure even when using an antiseize compound.
Also be sure to remove any wire-edge that may have formed on the tops of the threads.
One example comes to mind where a fellow tried to eliminate as much slop as possible, and a newly threaded barrel (with antiseize compound) was screwed fully into the frame by hand. The barrel was not torqued down.
It was snug slop-free fit, and could not be removed with an over-built action wrench. It had seized, the barrel had to be cut off and the stub bored out of the frame. The threads in the frame had been damaged during the attempt to remove the new barrel. The frame he started with was a very nice original Win Lowwall frame that had sported a round barrel, but the fellow decided he wanted a half-octagon instead.
What he got was just a hard lesson learned.

There is NO advantage to tight fitting threads. A V threads will alway center it's self and no matter what (if they are not a interference fit), only one side of the thread will make contact with the mating thread (female in this case).

W/o a thread mic or by measuring over wires, you really won't know what your fit is going to be. 

My suggestion would be to turn the thread until the thread will start, then go .003 - .005 more (if the dial reads direct on diameter. Half that, if the movement is on the radius)  on the dial and see if it screws on easily. You don't want any drag.

Be sure to deburr the tops of the threads, before you try it.

Testing with bolts, has shown the a 50% thread engagement (on pitch diameter) is strong enough to break the bolt, before the thread fails.

Most stainless steel manufactors (SS to SS threads) use thread engagements of 50% more than they do 70%.

Frank

Threads are very forgiving if you don't get in a hurry. 

I would recommend you get a half dozen old barrels and cut about 50 threads to fit a 1"  nut.

It will make you tired but you will learn faster than one at a time every 6 months. 

Some people have a ghastly time learning to hit the #8 high house bird in skeet. They might not learn in 50 or 100 rounds of skeet. 

But you can take a box of shells and shoot that bird over and over and after about 4 or 5 misses you will hit one and then you recognize the groove.
And the next one you might miss or hit and then you might hit 4 in a row.
And once you do that, a target you thought you would never learn becomes something that you learn to hit without thinking. You don't have time to think it is only muscle memory and hand to eye coordination. No brains required.