In my opinion, too old pseudobulbs does't really help. In that case they are even brown to some places and if they get covered by bark there is a possibility to rot.
Regarding media i suggest combination for so high temperatures. Not compress the sphagnum and it gives you the cool it is needed. Otherwise the bark will turn dry to fast.
Regarding hydrogen peroxide i agree with what you said. But is is of my preference to use it, because I cant find a better solution with snails(and i have used some). Unfortunately, other solution or removing the snails by hand, doesn't kill the egg snails, so they return and eat the new root tips of new growing pseudobulbs and finally the plant is too weak and die.
With hydrogen peroxide, I am sure that I will not have snail in the future, even if it takes some time for the roots to fully recover which by experience will not be more than 2 months.
Just for history
I bought plants with snails.
The one that I used H2O2 is about to flower for second time during this year. The new pseudobulbs have grown many roots.
For the other one i wasn't sure if it had snails so i didn't spray it. After some time i found eaten root tips and a snail. I used white eco pellets didn't work, i tried the classic blue pellets didn't work either. I tries a solution with cinnamon didn't work. I repot and spray the plant with H2O2, and now is the third month that grown some roots, the plant is too weak but I will wait until it recovers finally.
But all above advice, is what suits me to have healthy plants with lots of flowers in my climate and routine. Everyone have his one routines.