Mediums vs. deeps for hive bodies and package size?

I am going to start my 2nd year of beekeeping this Spring. Had a awesome 250 pounds of honey year last summer, just from 2 hives. Now I want to start up 2 more hives and I am considering using all mediums for the next 2 hives that I will be adding to my beeyard this Spring. I would like to compare and see the differences but i don't want to go the all medium route if it is not advised by others, especially since I had such great results with my 2 deep brood set up last year. I am a 35 year old young buck that is capable of lifting the deeps, but don't need to bust my back to prove it! I read a bunch about the pros and cons of deeps vs. mediums. It seems mostly like personal opinion. Just a few unanswered question I have are......
1. Does 3 medium(10 frame) hive bodies equal 2 deeps(10 frame) for brood boxes?
2. What size package of bees should I purchase(2 or 3 pound) if I end up going the 3 medium brood route?
3. Are there any "common" problems beekeepers have had by using the 3 medium set up?
4. When installing a 2 or 3 pound package of bees into a 3 medium set up, how many mediums do you start with at the time of install?
Feel free to answer any or all, thanks, juzzerbee.

1. yes
2. 3 pounds or two 2 pounds
3. Have extra money to spend on other toys.
4. one medium, unless you go with 2 two pound packages combined

>1. Does 3 medium(10 frame) hive bodies equal 2 deeps(10 frame) for brood boxes?

Yes.

>2. What size package of bees should I purchase(2 or 3 pound) if I end up going the 3 medium brood route?

Either works. If you expect much loss from shipping (and if they are going through the US mail I would expect loss), I'd go with 3 pounds.

>3. Are there any "common" problems beekeepers have had by using the 3 medium set up?

They don't get to know their chiropractor as well as they might otherwise...

>4. When installing a 2 or 3 pound package of bees into a 3 medium set up, how many mediums do you start with at the time of install?

One. A half of one is even better...