I'm currently using that setup, and have quite a lot to say about it, as I'm on my third "upsized" humi in about 3 months after hitting the slope at Christmas. I just (last week) got a Bargain Humidors Vicksburg Humi... a 500 ct, with the intent of replacing my 150 ct desktop and my small coolerdor. I've been using varying combinations of beads/CO in three different sized humis, with varying results.
I bought the CO XL when I first got into this hobby, before I got to this site, and before I knew about beads. To be honest, at this time... I'm not sure I'd pay the price for a CO. You've already got one, lol... so ignore that, and I'll keep blabbing.
I'm currently using the CO XL and 70% beads in my 500ct humi. Quite honestly, if not for the fact that I was a bit "scared" of the humi not levelling out quickly with my several hundred sticks in it, (due to the humi being new), I'd probably have just loaded it up with beads and be done with it. As it was, I used the CO XL for several days to season it, then added the sticks and beads, keeping the CO XL in there.
A few thoughts: The circulation provided by the CO is theoretically nice... but I'm not sure it is all that effective. My 500 ct humi was reading HIGH (78!) in the bottom where the CO was located, and low (63!) in the top for a few days when it was newly filled (after being properly seasoned). I would have thought the ability for the CO to circulate air would have remedied that a lot quicker than it did. (After a few days, it is pretty good... 66% up top at the lowest due to being opened and closed, and 70% in the bottom.) Plus... though you can feel some air movement around the fan, I just don't think the air moved by it is all that substantial... not like putting an oust fan in a coolerdor.
Currently, my 500ct is leveled out, and I'll probably be removing the CO XL at some point.
Some things to think about in a 150 ct - CO XL takes A LOT OF SPACE! Several bead containers can be popped in the corners of your humi without giving up an entire "section" for the CO, and will keep the RH pretty consistent by spreading out the humidity into several source areas... so despite the fact that theres no "circulation", your humidity is pretty consistent throughout. In my 150ct, I used 2 of the Heartfelt 2 oz short/fat bead tubes in opposing corners of the bottom, and one of the 1oz long/skinny tubes in the top. When doing that, the CO XL was sitting in its box, and the humi was holding humidity perfectly.
If you overload the beads in a 150, (double or triple it... the beads are still easy to fit), the recovery time for the beads is just fine. I LOVE the fact that the 70% beads put it right on the spot at 70%.
IF you decide to use both:
I'd recommend setting the CO 1% higher than your beads. If you set it below your beads, you aren't going to accomplish anything. Theoretically, the CO (if set 2% below the beads) won't activate until the beads are emptying and can no longer keep the RH at their set level. And even when they CO is running, the beads will still be emptying, albeit more slowly, until they are dry. The beads will be pretty useless if your CO is set below them. If you set it above the beads by 1%, the beads will remain full... and will only operate if your CO fails for some reason, or isn't actually circulating humidity to the other side of the humi.
Anyway, in a 150 ct... I don't know that you need both. COs seem to be fairly reliable, and I imagine, like the rest of us, you check your humi pretty routinely. If you leave it for weeks at a time... then I think using both is probably pretty smart.
You'll probably have fine results using either beads or the CO. No harm in doing both, except for the lost space.
Based on my experience thus far... in a 150, I'd just go with the beads.
(I am a 70% guy... usually, due to opening and loss, the 70% beads are keeping the humi at 68-70, and when they drop and need to be refilled, I notice it when they are 64-65. If I were doing that with 65% beads, I'd be dealing with 63-65, and dropping to 60 when needing to be refilled. Plus, it is winter.)