You don't need to choke it any more than it already is. I have been shooting a .410 with TSS for a couple of years now. One is a Winchester 37 that is 60 years old. The other is a Stevens 311 that is Full/Full. Both kill turkeys at 30 yds. and hill still put over 100 No. 9 TSS in a 10 in. circle at 40 yds. I hold my shots to 30 and under by personal choice. Unless you are gonna buy a new gun I wouldn't worry about it.
i shoot a pump mossberg 410 with factory full, it works well, mine are closer to 9.25 tss, id shoot it and see what it does before i got carried away, hal might have some #10 tss u might be interested in trying, if your not getting the patterns u like and run into a hard time with chokes
IMO,You need to rethink that 3 yr old deal.......he doesn’t have to pull the trigger to have a great experience...however you decide to go ......be careful
The 410 shooting 3" with TSS has some kick to it for a little kid. My son was 4 when I first let him shoot it. He was shooting target loads fine and then I loaded the TSS load and he quit shooting for the day after he shot it once.