If you're set on the land near home, which apart from size has many advantages, then you could manage that but only with the help of some careful management and the purchase of enough hay or silage. Use the paddock with the best shelter over winter, and if need be segregate it further with electric fencing and accept that spring regrowth will be slow there. Feed them there, make sure there is
some dry ground, and make sure your fluke doses are up to date over the winter. Once you hit the growing season keep them out of there and use the rest of the land, which should last you over the summer and into early autumn when the grass runs out again.
If you want to go for the bigger field, you will need to restrict access for your small flock throughout the year - more electric fencing! Get the excess grass cut at the right time, keep some for yourself and sell the rest. Then grow your flock slowly until you need another field... Don't worry too much about shelter.
Friend's farm
? I wouldn't, unless I couldn't reliably find the time to tend to my own flock.