First time playing Merchant Republic, holding question.

Hi,I've just bought The Republic and decided to try some sweet democracy. I started as tribal Scotland in 867 and created MR. The game is relatively easy, vikings were wiped out or converted to Catholicism, so the realm is really stable.But my question is: as I have so many empty slots to fill, what type of holdings should I build? As a feudal in previous games, I tend to build cities for cash, but I have already a lot of cash from trading posts, my palace and my cities.I have an idea to built baronies for levies, especially in my capital duchy (Albany). Is this right? Or should I fight with my retinues and mercenaries?And what kind of vassals should I create? Now I have two vassal Duchy-level republics (just republics, not merchant republics), Republic of Moray and Republic of Orkney. Maybe feudal duchies are better?I try to avoid bishoprics because I am Catholics and fuck you Pope and your taxation.Thanks for any advice. via /r/CrusaderKings http://ift.tt/2sstmxc