Fellow triathlete here. First, my view is that for IM, you can never have enough base! BUT I see where you’re coming from so you can do what is suggested ^ and jig plan-builder to give you more build. 6 months is just about enough time to do a full base/build/specialty cycle and if you’re coming from less cycling training, base might not be a bad idea.
When’s your IM? Feel free to join us over in the thread where we talk about IM training: The Ironman Training 2020 Thread - #3788 by Scheherazade