Actually, it WAS a sizeable percentage, at the time Nova was released, and I think it has now shrinked. RlëD data is used on Macs if the color depth is 16 bits (thousands; notice Nova will change depth to thousands at launch, and if you try to get it back to millions while Nova is running it will popup a message saying to revert to thousands before continuing...), and Rlë8 if the color depth is 8-bits (on Macs still). Now, the PC port has been made to use only the RlëD data, whatever the color depth is, it's dithered at loading or runtime (not sure), and if Rlë8 are included in the PC Nova files it's because no one bothered to remove them. Now, when aprosenf has made EVNEW, and especially when he announced it, he said he was having problems with the palette data for the Rlë8, and that's one problem he has not solved yet, and maybe won't be solved since there is not even any way to test the Rlë8 with PC Nova. aprosenf says in the docs that if you wish to include Rlë8 data, necessary only for 8-bit Mac users, you'll have to ask a Mac plug-in developer to do it (using En/DeRle), but you usually shouldn't bother; I really don't know if you'd be right not to bother, I really have no idea on how many Mac Nova people have a monitor/video mem unable of doing 800x600 on 16 bits. I don't know how Nova will react on Mac if the color depth is set to 8-bit (and there are two cases here: the color depth can be set to 16-bit, and can't) and Rlë8 data is not present. This is essential to know for the thing to tell in your ReadMe if your user encounters the problem: "if you experience -MacNova problem when 8-bit and no Rlë8-, you need to set your color depth to thousands before launching Nova with -your plug- installed; if you can't set to thousands, then this plug-in cannot be used with your config yet; maybe a posterior version will, contact me to inform me of your condition"
I'll do some testing ASAP.