try for scenario a.
if you have to go for scenario b, remember that it is usual for tennants to be on a 6 month FIXED contract initially and then 1 month notice. I doubt you will find tennants who will agree to one month notice from the off (would you?). Also its a bad idea to cut the finances so fine when tennants are involved imo - the house could be empty for longer than you thought, the boiler could go - anything could happen that would instantly wipe out the 150 and more.
think scenario c would be better, OR scenario d: get rented accom, get a job in the new town and cut the price until it sells. will mean you have less money to put into a new house, but happiness is more important.