Yes you still need to leave the gap. You want to put in 100% waterproof clear silcone between the gap and the tub, like Tap Silicone Max 10.1 oz. Clear 100% Premium Kitchen and Bath Silicone Sealant (model: #08668). I would then install the Zamma Starry Light 5/8 in. Thick x 3/4 in. Wide x 94 in. Length Vinyl Quarter Round Molding (Model # 015143850) to cover the gap and finish it off.