Sunset is not the greatest from Thalassa, so preferred time would be around post 9pm, when you can enjoy the night party. The prime sits needs to be pre booked, please call thalassa goa for confirmation.
For budget stay in Fontainhas you may check Hospedaria Abrigo De Botelho or O Abrigo villas, or if you prefer hotel then you may choose The Hawaii Comforts in Panjim
I visit Goa once every year, I prefer to stay in Radisson blu cavelossim or Dona sylvia south goa, Both this hotels have private beach and real worth staying if you want a leisure and relaxing holiday. If you want more fun and happening place then choose Palolem in South Goa. If you want to stay in north Goa with family then stay at Candolim many hotels and good cafes are available with live music.