Watts are watts. Yes there can be a mental aspect, but in climbing it's mainly about w/kg. I've ridden big charity rides/fondos in the NC mountains with 100'/mile of climbing and people from the coast do just fine but they are strong and light.

Get your w/kg over 4 for an hour and you'll be OK. The one thing I've noticed is that on certain long climbs with short, steep sections (15-20% grade) I do have issues b/c I haven't trained enough with low cadence. I can put out over 4 w/kg with a cadence of 90-100, but I find if I have to go down to 60-70 for a while it decreases my average watts for the climb. I'm working on pushing bigger gears on the flats now to remedy this. It's something you may consider also.