Hi Bronzino
Congratulations on your new Syrian hammy! Here is a company that makes perspex screens for hamster cages, attached and detachable with wingnuts
Enclosure Screens And Guards Archives - Viking Laser
You may find that he bar bites mainly the front if the cage. You can try using cardboard and loo roll inners, or even ink free envelopes, but be careful of sticky sellotape or potential toxins. I stopped feeding my Syrian through the front bars as he would beg for food and then bar bite if he wasn't getting any. I feed him inside the cage as he loves the interaction (and so do I)