I think that the first thing you need to know is how much you loose to evaporation, using your setup.
Let's say your final target batch volume is 5gals and you know that you usually loose 2gals to evaporation. I would boil 6.5gals, get around 4.5gals post boil and complete with cool water to reach your target.
I find it easier to get the post boil a little under the target volume and complete with water than end up with more than 5gals or wort, which you can just leave as is knowing your OG will be lower, or have to boil it more to reduce it.
Also, regarding mashing volume and sparge volume, mash volume or strike volume will be defined by your grist and mash thickness, that it is. The temperature of the strike water will be defined by your mashing temp.
For the sparge water, I would warm enough water to have some left over, this is not a precised volume. If you do a batch sparge, let's say you mash 10lb of grains for a 5gal batch and used 4gals of strike water, you would mostly drain about 2.5gals of wort off the mash tun once mash is completed (loss to grain absortion), adding perhaps 2gals of sparge water, stir and recirculate and drain again, redoing this until you reach your boil volume.
Best if your sparge water in under 170F to avoid tanin extraction, like 160 to 165F is what I try to use.
I do fly sparging so I heat about 5gals of sparge water and by the time I collect all my wort I still have 1 gal of unused water.