I've been flying my 29mm Callisto since 2003. I only flew F & G motors till I certed on a scratch built in 2008 and then threw a H97J in the Callisto. On Monday of LDRS I drag raced my Callisto on a H165R against a friends 3", 6 lb., DD rocket on a EX I400. He had a Pyrodex pellet in the ex motor so he got off the pad first, but the Callisto passed him about half way up. The Callisto only went a couple hundred feet higher then his rocket and his altimeter chirped 2028 ft. It was a pretty calm day, 5 - 8 mph and the Callisto landed about 350 ft from the pad.
My Callisto came with a 24" chute with a 3" spill hole. It comes down plenty fast enough. I usually fly it with a larger chute unless the wind is in the 15mph range. In the six years I've flown it, on upwards of 50 flights, I cracked one fillet and that's been it. I've also never came close to losing it.
I would say: Do your cert on the Callisto and use any of the 29/180 case H motors. If it's a calm day and/or you have a large field, don't be scared of 29/240 load like a H250G. If you have a calm day and a large field you could go for the I200W in the 29/360.
Another piece of advice from flying mine, if you fly on a calm day <8 mph winds, use the longest delay available for any motor you fly. If it's a little more windy, use a medium delay. You can sim the different motors and most will come close with the long delay, but if it's a little breezy and the rocket tilts over early, you'll be better off with the medium delay and a slightly early deployment. This especially important with F & G motors. The Callisto is designed to be stable with the largest 29mm motors so when you fly it on F and G motors, it will be pretty over-stable and weathercock quite a bit. You'll see some of that on the 29/180 motors, but not as bad. For future reference, if it's windy and you're flying it on a F or small G, tilt the pad 5 to 10 degrees with the wind, it will weathercock to a vertical flight.
If you're conservative about your flights, I might not be the best person for advice, I tend to go for the altitude. I didn't cert on my Callisto, I scratch built a DD rocket and used a Loki I110W moonburner to get 4,200 ft. for my L1. I couldn't get that altitude from my Callisto, but it is still calling me to use that I200W.