l2h good ?... For some one just getting into turkey hunting and not knowing much about turkey guns / chokes / turkey loads...
A 20ga is prob the minimum I would use for a turkey...
you really need to get your self some decent turkey target... Primos has some of the best... They are actual x-rays of a turkey neck... so it's like shooting at the real thing

I usually burn copy's of them so I don't have to buy a lot...
Next you need a decent turkey choke... Tru-Glo, H&S Strut Undertaker are a few decent ones... Next you need some good turkey loads... As far asI'm concerend Winchester are the best!!! I would recomend 5's or 6's
MAKE SURE THERE TURKEY LOADS not upland game loads
Now for how far... I would set my first target up at 20 yards...(use a tape measure)

Shot at 20 and count the hits you get in the vitals(brain/neck vertebra)
You'll hear a lot of controversy about this but I say at least 4 or 5 hits to virtals...
Try this at each yardage(20,30,35) until the number of pellets you get drop below 4 or 5... That will tell you how far you can shoot your 20 gauge
now remember you need to shot more than one target at each yardage... I like to shot 2 or 3 at the short yardages and shot maybe 4 or 5 at the farther yardages... Do a average.
Say at 30 yards you take a shot and get 4 hits in the vitals and then set another target and shot and get say 7 hits, then set another target and shot and get 1 hit you could say your averaging 4 hits in the vitals which in my opinion is the minimum
I hope this helps you not wound turkeys this spring

GOOD LUCK!!!