Go with the
manufacturers specs for tyre inflation - that's the best rule of thumb. Going too hard on PSI can actually make it worse due to aquaplaning and you get a 'smaller footprint' from the tyre on the road if you've cranked up the PSI when there's actually no need to do so when carrying the same load and wrecks your wear ratio anyway!.
I've never seen hail bigger than pea size up here but there's certainly huge hail in the eastern states. You should never cover the windscreen with any kind of perspex or other plastic coating as it will only obscure your view even further, something you don't want. As for covering it with some kind of non-shatter film - that's illegal anyway since your only escape exit may be the windscreen and you/rescuers need to be able to smash through it.
Most people just make up some sort of mesh screen - you can get mesh screens for your car from camping or outdoor/4wd outlets but with most cars they're not an off-the-shelf option that's easily available and you'd have to make one up yourself. It would be somewhat a waste anyway because if the hail is that large it's going to dent and even break the mesh and if it dents it severely then it would only take a direct hit in the same spot to crack your glass.
Broken windscreens/windows are victims of large hail and most folk just replace the glass - although if there's big hail within the core
you probably should not be in that zone anyway for your own safety. Better to follow the storm or wait until that area no longer poses a danger and then drive closer to collect/photograph the hail.
Of course it's not always a visible thing when the heavens let loose...so the best rule of thumb is collect the hail later once it stops hammering down. Your car would be a tad messed up with all sorts of damage from large hail .
There's no secret or special things to do with your car - remember to keep it out of harm's way and you don't want to be spending money which you don't need to as far as storm mods. Keep it roadworthy i guess - the safer the better and the cops won't ping you either.