I just got this skill not too long ago, and I figured it would be good to use as a searcher for Slifer since it is prismatic. But the problem is that some of the support cards I want to use in the deck are glossy, and for some reason, the game does not let you choose multiple copies of ONLY non-glossy/prismatic cards if you still have a shiny one, too. I have 4 Ra's disciples, but no matter what I do, the deck editor forces me to put the one glossy one in out of the three. I have tried everything I can think of to avoid this, including only choosing "basic non-foil" as an option. It's annoying, because it gives me less of a chance to draw Slifer if I put other glossy/prismatics in my deck.
Even with the correct settings (assuming you did that right), you must have THREE non-glossy/prismatic copies of the card you want to add, otherwise you will necessarily add glossy/prismatic cards if you have them. I just added THREE basic non-foil Mooyan Curries to my deck, even though I have more than one glossy copy.
Can you please show or explain to me in a step-by-step process how you did it? I do have three non-glossy ones, but the game keeps forcing the fourth (glossy) one in as one of the three in the deck, always leaving it like this: 1 glossy Ra's Disciple, and two non-glossy Ra's Disciples in deck, with one non-glossy Ra's Disciple back in with the spare cards in the deck editor. It's always the same!
Sounds like a bug then. Make "Basic (non-foil)" the first priority using the settings, then add the cards normally. If you have three basic copies, then three basic copies will be added to your deck. Make sure you actually have three basic copies by checking the card catalogue or the card trader.
I guess you must have done that wrong. I suppose by 'basic nonfoil' you mean the filter right? That only filters out cards you ONLY have in foil.
What you need to do is set priority of card addition. In PC it'll be under the skill. But in mobile won't be so obvious; you need to click any card 1st and setting will be at the bottom besides related card.
I don't know how I did it exactly, but once I found this and played around with it a bit, the glossy Ra's disciple is not one of the three in the deck anymore. None of them are shining now, and I am thankful for that.