Don't be so scared of porting your code. On my current work, we have a few thousand lines of python (spanning different services and supporting libraries) throughout in ~18 months and we were blocked by pika (a module for communication with AMQP servers).

When pika got a python3 compatible version, we ran out of excuses to not use python3, but still my colleague was worried that "it would take too long to port things, and our-code-is-working-so-why-bother". I decided to try it anyway, and it took me less than a lazy Friday afternoon to run 2to3 on all the packages and get the tests to pass.

Given that your work is with scientific computing and (presumably?) you have control over the deployment environments, I'd really recommend that you avoid do the switch sooner than later.