Bal green star. It's ok but I very rarely I use it as the cement adhesive is much better as it don't break down. Best thing for you to do is spread some tub addy on a tile which is not being fixed and leave it for a week. Then stick it in some water over night then use a scraper to remove it. It will come off in seconds so if there is any moisture behind the tile due to a leak then the adhesive will become sloppy. Also tub gear won't dry if over a certain thickness or size tile unlike the cement based. Even a splash back where u want to be finished in a day the adhesive will takes months to dry or may never dry as your grouting same day.