I'm gonna try to answer everyone in one reply.
Baja_costero: yes i always try to water in 2 passes when i have the time. It helps a lot with getting the soil saturated but most importantly reduces salt deposits which are a real problem for me worh out very hard tap water. Acidifying helps but flushing a second time is key.
Daisyl: now i respectfully have a couple of prroblems with your reply
1. I'm not asking how to care for my outdoor plants. I have several 100s living happily. I'm asking for 1% of them how to simulate nursery condition to get them to look plump and full like when you buy them and before subjecting them to more extreme cinditions.
2. Not sure how my locaction is relevant. Since the start, it's written in my signature (?) that i'm in zone 11a and have lots of winter rain which is more than enough i believe.
3. Why not water more often? I try to water as soon as my plants dry out so i can't water more than that. What i'm asking is how to get the plants to absorb more water/lose less from conditions
Baja_costero: not thr canary island but quite close relatively
Consider the effect of heat more than light: but they are mutually exclusive. The more sun a plant receives, the more hot it gets and the more water it loses (mostly from its soil). This is thr first time i've heard about such mild weather i your area. I thought for sure you hit 90s and 100s in sunmer.
I have lightmeter in my smartphone (it's free from the app store) but i'm struggling in finding the necessary level. All i find online is cannabis related.
I found it usually that the sun is strongest to the east which is rather weird. This has caused my columnars to have a very annoying tilt to the east.
I think i'm gonna take you up on a 50% shsde cloth with all day sun rather than part sun. Yes i'm not a fan of soft plants but i would prefer that over succulents with literally paper thin leaves. I've never really used a shade cloth and all my cacti go immediately into full sun (after a couple of weeks part sun to acclimate). I really like aggressive looking spines and i'll take that any day over fast growing plants. My pride was an eriosyce bulbocalyx thst i grew from seed and it took 7 years to get to a 4 inch pot. But man it has some crazy spines. You could not see the body unless it was well watered. Unfortunately it's dead now. I attached a photo of a bunch of cardons i grew from seed. They have crazy long and thick spines and are starting to look bluer thsn my pilosocerei. A buddy of mine grew his at the same time and they are substantially bigger than mine but have weak thin spines and look very green with not a hint of blue.
Back to replying, truth be told, i'm not even half as brave as you to leave my plants out in winter though they would probably take it. They could use a wash and some acidic rain to remove carbonates but they'll have to wait for spring rains. Boy do they look amazing after some rain, especially the barrels.
Now for soil, i would love to use coco fiber since i've only heard good things. The thing is i've been using the same mix for years and often pot plants up rather rhsn repoting everytime. Using coco fiber would mean i have to repot every single plant or else there would be a difference in drainage.
Anyway thanks for all this great advice!
Mcvansoest: no just stunted though thry get plenty of water. As soon as i move them to part sun they hit the kickdown switch. Though i water in 2 passes at night to give them time till morning to drink well, i'm starting to think some plants are not well hydrated.
As you say, watering almost becomes a full time job so i'm only gonna soak the succulents and the subdenudatas. As for adeniums, for me they live with the mature cacti. They take full sun easily which makes them flower profusely and get the same water but so much more fertilizer. I bring my plants out in very late winter to early spring and i don't water much in this period since it rains very conveniently once a week

i have to say that they look much better in spring and they only have a bunch of roots coming out of drainage holes in spring rains (never in summer). Come to think of it though, last year they were in rain for 7-10 days straight and not a single plant burst from too much water. So maybe my soil is not that water retentive but i guess it's good safety measure.
Oh and btw, i often don't water in midsummer since i'm mostly away but a big number of plants are dormant. This way i don't have to look for who needs water and who doesn't. Better safe than sorry
I blabbed too much. Thanks everyone!