The best is to use the Quick controls, as they can be saved in track presets, allowing you to retrieve the settings already done from one project to another. The problem (and this is a feature request that have been done countless times) is that we have only 8 quick controls at our disposal (24 would not be a luxury, IMO), which is rather limited for a VSTi such as Sylenth1.
To extend the number of VSTi parameters subject to a remote control, you can indeed use a Generic Remote definition (you should do so, actually, would it only be to use the MPD32 to remote control, at least, Cubase itself : works fine, here).
BUT there is a huge limitation that persists from one Cubase version to another (and which has also been the subject of feature requests since a long time ; see this recent one, in example : Steinberg Forums…) : the Generic Remote control settings for anything outside Cubase itself work per channel. To be as clear as possible : let’s say you setted some Sylenth1 parameters while this one was using the 5th channel of the VSTMixer. Now load another project in which Sylenth1 uses the 6th one : your settings are lost or, more precisely, affected to parameters of another channel.
From which, either you do as much project templates as needed and create a Generic Remote settings bank for each of them or create as much banks as VSTis used, and carefully load the appropriate bank relevent to the VSTi you are using, but the latter is quickly a mess. Both solutions can be done in the same XML definition file (use the ‘Rename’/‘Add’/‘Delete’ buttons at the right of the Generic Remote definition bottom panel). I choosed the former solution, still waiting for something more efficient, as adding or removing a channel is impossible if you want to keep all the remote definitions usable…
And don’t talk me about the brand new ‘Remote Control Editor’ : I know by experience that it is useless with the MPD32 or any Generic Remote definition, by the way. Another feature request which may never be taken into account…