I'm so tense about tense!

Well, at my last writer's group meeting, I came to an impasse.

I'm at about the 35,000-word mark in the second version of a novel I'm working on. I've got two main characters in two different time periods: Saint Columba in 560AD and Rose 2007AD.
I've been writing both sections, which more or less alternate, in present tense. My readers, both of whose opinions I respect, told me that my choice of present tense in the Saint Columba sections is getting in their way. They say it sounds as if I'm trying too hard.

I know they're right. I find myself as I write forcing the present tense. I wrote the whole 100,000 words of the first version in past tense. Then I purposely decided to use present tense for the second version--I think I wanted it to sound more immediate and perhaps more contemporary. It seemed like a good idea at the time.

Now, I'm debating about whether to switch back to past tense. I really need to make the decision before I go any farther because it affect every sentence I write--every sound, every word. It will be laborious to go back and change the latest 30,000 to past tense--it's just not as easy as just switching tenses--some sentences just don't sound right anymore when I just switch the verb. Hmmmm.

So, this past weekend, I started the next section and I switched back to past tense. It feels easy and comfortable--and somehow a cop-out. But maybe that is because I was trying too hard to be something I'm not yet. I don't think I'm a good enough writer yet to pull off present tense, especially in the historic fiction sections where I have to refer to the past and then the past of the past and sometimes the past of the past of the past.

I'll finish this next section and throw it to the lions at my next writer's group meeting. I hope it survives:-)