That's an interesting question
First off, the Reo Grand is a mech mod as you know and that means the power will drop as your battery discharges. That means if you set it up at 0.22 ohms giving you around 65 watts on a charged battery you'll be down to around 46 watts by the time you'll probably want to swap batts. I've run my Reo Grand at 0.25 ohms and it did that quite happily. If you want to average 60 watts you'll have to build close to 0.20 ohms or slightly less. The range in power then is about 70-50 watts.
Going that low in resistance on a mech mod has its risks. I use a good DMM that I know well and have compared to other meters so I'm comfortable it is reasonably accurate, or that I know how much it's off and can compensate.
These days when I want to vape higher power I use a regulated mod with 2 or 3 batteries, because the power is split evenly between them. Both of the regulated mods you're thinking about are single batt mods maxing out at 60 watts. The battery amp draw with them at 60 watts will max out at around 22 watts and most IMR Li-ion batteries are safe there. If something goes wrong like a shorted atty, you're safe because of the electronic safegaurds.
Of course you still can't go past 60 watts with them no matter what battery you use, but you can with a mech mod. I don't know how much power a Reo Grand can handle, but I suspect the current ones can go over 60 watts if you build for that. There are good 30 amp batteries available too, but they won't last long at 60 watts. Then again, none of our batteries will last long at 60 watts if you're using one at a time.
But mechs have risks that are not there with regulated mods and the power won't be consistent.
So, how much power do you need for a good vape? And how do you feel about the risks of running higher power in a mech mod, and the power drop off?