I think he is talking about the photoresist method, not the toner transfer method.
I agree that there is so much written on the subject that a few minutes of searching on his part would help him define his questions quite a bit more.
For starters, he needs to define the photoresist he is using. The one I use (Injectorall) is attacked by HCl/peroxide, so I stick to ferric chloride or cupric chloride. All photoresists are made from a substituted organic resin. Toner is a plastic medium. The organic resin is more susceptible to strong oxidizers, such as HCl/peroxide. I suggest ferric chloride for starters. With success, he can try other etchants.
Most important, he needs to calibrate his system. That means taking a piece of photosensitized board and exposing sections with a simple mask, such as "><" , for different periods, then develop and etch it. That will establish his exposure period. There is no other way to accomplish that, that I am aware of.
Finally, as for developer, read the instructions for your photoresist. Some require relative weakly alkaline solutions made from sodium carbonate; others require strongly alkaline solutions containing NaOH or KOH. For mine, I use the alkali metal hydroxide with excellent results.
John