I work in a darkroom with a mirrored wall, and it is fine.
If you note a particularly bright spot on a ceiling or wall, just tape some dark paper there.
When you rewind your films in your ME Supers, you will be able to feel and hear the film coming off the take up spool. Just stop there, open the back, and tear off the leader.
As for the wetting agent ...
Do you have a small measuring cylinder - say up to 45 ml?
If so, just measure the total volume of, for example, 30 or 50 drops.
Then calculate what the total volume of working solution you would end up with if you dilute that volume according to the Ilford instructions (1 + 200).
Then divide that total volume by the number of drops you used, to get the volume of working solution you will get from each drop.