Your wpm totals are impressive for one week! Good for you.

I like that you are purposefully trying to maintain your QWERTY while adding Colemak. That might be a good strategy for those that will have to switch back and forth often. I type on Colemak about 98% of the time, so it's not a big deal for me. But, I can see for many it would be important, depending on your situation.

I learned Colemak around a year ago like you and started as a proficient qwerty touch typist (~110 WPM). I did it by initially ditching qwerty though. Once I got comfortable with Colemak around in the mid 80 WPMs, I started picking up qwerty again pretty quickly at my workplace. I guess what I'm saying is if you're really proficient at qwerty I wouldn't worry much about losing it permanently especially when you'll be forced to use it again. And yeah, they are indeed pretty similar layouts.

I didn't double my initial typing speed though, just reclaimed it, and type no faster in either layout. I was satisfied with this, so I left it at that though. I'll leave you to decide whether you think the comfort differences will be worthy once you reach a comfortable speed in both, if that's your goal :).

> My goals are to increase my typing speed while preserving the health of my wrists..

A noteworthy goal! Typing tests can be the highest burden possible, as I've found out..

I have been using Colemak exclusively at work for the last couple weeks.  While it has greatly improved my proficiency at Colemak, it has also destroyed my ability to type QWERTY.

Colemak: 65wpm @ 96.94%
QWERTY: Gave up.  Can't type it anymore without looking at the keyboard.

It's been almost two months now.  I find typing in Colemak to be mostly pleasant, although my speed seems to have hit a plateau.  I haven't been actively practicing over the past several weeks, something I plan to pick up again.  I won't consider my transition complete until I break 100wpm.

Colemak: 62wpm @ 94.68%

I know, but I'm coming from a 110wpm average in QWERTY.  Part of the reason for my switching to Colemak was to further improve my typing speed.  I don't think I could have gone any faster in QWERTY, my fingers were fighting with each other.

Any improvement in typing speed will be marginal at best. Most of the improvement comes not from the layout itself but by learning a new layout from scratch you can get rid of old bad habits start again from the ground up and hopefully eventually overtake your performance on the old layout but it will be a long journey.

About three months now.

69wpm @ 96.91%