With the water being so warm you need good reliable PVA that will actually make it to the bottom wioth out disolving.
These solid bags are the best ones according to Gillhams Bailiffs. But you are a fan of using the Funnel Web system then double bag them, this will prolong the meltdown time meaning it will reach the bottom before disloving.
Braided PVA String has an ultra-fine woven structure that means the PVA has a higher surface area for consistently quicker dissolving times, especially in low water temperatures.
Plain PVA Bags are suitable for use with oil-based liquid additives and flavourings. The perforated PVA Bags have multiple small holes over their whole surface so pockets of air cannot remain trapped inside the bag. This makes them ideal for distance casting and ensures they sink rapidly in deep water.