Well, halotestin is normally used for strength and hardening prior to a contest. It gives you a good pump, great hardness and motivation to keep lifting during the last 45 weeks of your pre contest routine when calories are low, carbs are low, etc.
I think it would work well stacked with sust. If you doing this for a bulking cycle what are your planned doses? I would use the halo one of three ways,
If you are doing a twelve week cycle for example:
15-20 mg a day for the first four weeks
or
15-20 mg a day for the middle four weeks
or
15-20 mg a day for the last four weeks
I think for a bulking cycle I would prefer to use it at the beginning stacked with 750-1250mg of sust depending on your goals and experience.