I'm very sorry for being a rookie and all but what does "Jounce" mean?
It's a situation you want to "avoid" the rear axle bangs off the rear bump stop. Shocks and springs work together by absorbing the upward energy from bumps, if you hit a bump and you don't have enough suspension travel in the rear ... the process gets halted and the energy gets "transferred to the frame" through the unaltered bump stop location to the vehicle.
In the "Real World ..." that means "instant unanticipated" change of direction! My most spectacular example was back in the day with a full "Koni" Fiero!
80 mph sweeper with a mid corner bump ... I knew it was there (the bump) because, I'd hit it many times in my Merkur XR4Ti (Stock) at 100 or so. So 80 in the "modded" Fiero ... no big deal?? Yeah not so much it was late at night in Ca ... all the "nut balls" prowl the canyons late at night.
I hit that bump hard and the rear end lifts up and I'm in the other lane??? Still pointed in the intended direction since I never lifted but my eyes got pretty big!
But think "Unlimited Hydrofoil" and the boats skipping off the waves ... your "Vehicle" will do the same thing if you don't have enough rear suspension travel!
In San Jose Ca we have a popular stretch of road with some really bumps! And it often takes out high dollar, modded cars with full coilover suspensions! Super stiff springs and limited suspension travel ... the unknowing hit those bumps on full kill and they don't make it to the bottom of the hill!!
Happens all the time out there. Most stock cars with full suspension travel were actually faster down that hill than the full kill turbo charged, coilover equipped monsters!!
I actually shattered a headlight one night going up there in my "Modded Mini Truck" Toyota. A Mustang though ... he was going to pass me up the hill??? Yeah ... I don't think so!! Good Times Good Times ...
But yeah as I am want to say ... I give sound advice ... I don't often follow it so ... don't drive like that on "public roads!"
Pretty sure "Norcal SS" can tell you how much clearance you need to have with your vehicle at rest.