Well like I said in your last deck, I'm not so experienced with Yubel decks but I think I can help a little here. Now, Yubel decks are fun decks that can be competitive with a good player and a good build. Inca decks are fun decks that can be competitive with a good player and a good build. But both together...not so much. The reason I say this is that they don't seem to have much in common. What you really need for incas is a boatload of level 5's and 3 of each tuner. Yubel doesn't really provide that in and of itself. So to me it seems like it would do better in separate decks since you're just cutting down on support to add in a Yubel engine. Not to be mean or anything, just think it would work better that way. As for synchros, this is pretty standard:
Trishula
Stardust
Colossal
Scrap Dragon
Red Dragon Archfiend
Black Rose Dragon
Brionac
Ally Of Justice Catastor
Magical Android
and you want to ALWAYS max out on the 15 limit. What other synchros you use depends on the deck