cannabutter questions

hi guys...a few cannabutter questions...please bare with me as i am new to this... :)

having not much access to a kitchen i only get around 3 hours to simmer the cannabis with the butter

so

1 do i need to use water and why?

2 if i leave the plant matter in the butter does it make it stronger?

3 if i leave the plant matter in the butter does it make the effect last longer due to the time it takes the gut to process it all?

4 is 3 hours long enough?

5 i have a mate that just uses butter and cannabis...simmers for 30 mins...and doesnt strain...his works fine...is it because low simmer time requires the plant matter to be left behind for it to work?

i find this all so confusing

i must stress that i am doing this for medical reasons...not for any other reason...so i dont need to be knocked sideways with this stuff :)