Options from my head FWIW:
1) "double tap" the meter
if allowed by your utility/local jurisdiction - run that feed to a 60A disconnect, then to the shop panel. Double tap means run another set of wires from the same lugs under the meter that feed the house panel. Main issue here
if allowed is that you have to pull the meter and the utility will have to grant permission (or come and do it). Also, the lugs in the meter box will have a torque spec in in/lbs and you'll want to make sure you follow that. This is how my shop gets it's power.
2) breaker in existing panel, run to shop panel. Main breaker optional in shop panel, good for local power shutoff mainly. I use a 125A panel in my shop with no main. The disconnect/breaker next to the house panel handles that and I'm fused at 60A.
3) if existing house panel has "extension lugs" or some such, meaning a way to carry the feed out of the panel to another (would likely look like the lugs for the feed from the meter) then tap off there to a disconnect, then to the shop.
For the distance stated with a 60A disconnect, I think #4 will be the wire size. Double check that for sure. I use #4 for my overhead, then about 24' in a 1 1/2" conduit. #2 is not that much more $ for a run of that length and you'd have extra capacity, which never hurts.
I'll be staying in a holiday Inn Express this Saturday, so I must know what I'm talkin' about.
200 amp service is overkill for a 900 sq. ft. home.
We're at 1600 sq/ft and the 100A house service is plenty fine for us. However, we use gas heat in the house.
