Had previously considered, but now think I'll give it a go. Have about 150 ft/lbs + on the puller trying not to break it, but will definitely remove it to cut so it doesn't explode off.
If you aren't in fear of breaking that particular puller, then it isn't tight enough. And you need a real pitman arm puller.
OTC (8150) Conical Pitman Arm Puller https://www.amazon.com/dp/B00061SMS0/?tag=wranglerorg-20