Live casino is a horrible place. It's all young Eastern European women wearing satin corsets and having to talk to people constantly flirting and sending inappropriate messages.
There are calculators for wagering that recommend spin size and calculate bust out chance. The wagering is based on the winnings. So say you won £13 from 10 free spins and it has 20x wagering so you would have to wager £260 before the money was yours.
The best strategy is high rtp, low variance, min spin max lines. Until you get a big win/bonus and then recalculate as it's usually better to up the spin size.
Some people prefer to do big spins on a medium - high variance slot, that way if you win, you get a nice win to hopefully carry you through wagering, or you bust out nice and quickly and don't waste time.
I do either of the two, depending on the slots available and the wagering requirements.