I suggest you to use OTClient. It works with 8.6, it is highly configurable and supports extended sprite limit and transparency. If you do so, you'll need to use ObjectBuilder to convert your spr/dat files into "extended" ones (pretty easy, just make a back up of your files and save them as extended using ObjectBuilder) and always work with tools (RME, ObjectBuilder and item editors, for example) that supports "extended" files.