I definitely transfer a lot of weight through the feet. As soon as the weight goes more on my arms I feel the foot placements become useless and basically feel as though my legs/feet are dropping out from the overhang.
What part of the shoulders would need strengthening in relation to steep ground?Any advice on what I could do at home to help improve this style overall using the fingerboard/pull-up bar?
I used to have this exact same problem you describe 'til I started deadlifting- it seems to make your lower back stronger really quickly which lets you get that push through your feet to create the tension. I imagine you're aware that there's an epic thread on deadlifting on here.
Physically, I saw your "core" program and it is far from anything that would help with steep climbing. the intensity and the specificty is simply not there.
It's worth pointing out that a lot of good climbers also struggle with the Cave on their first visit as it's so beta intensive. That punter Megos only climbed 8a . I think you just need to bite the bullet and do more steep bouldering despite how demoralising it may feel to begin with.
I'm good with my feet and usually use technique to get around not being strong. Where my mates will just lock something out or throw for the hold I'm usually using the intermediate shit crimp with some gnarly heel beta...
One thing worth noting: 'technique' is not something which only applies to vert, nor is using the gnarly heel static beta always 'better' technique than 'just throwing' for a hold. Chances are your technique for vert stuff is pretty good, but if you're not used to climbing steep stuff then your technique for it is probably pretty poor. The timings, the movements, the body positions are all different. Good with your feet on vert doesn't mean you'll be good with your feet when it comes to pulling into holds on a roof, toe hooks etc. Watching Steve Mac in Santa Linya compared to how Bolger, Sharma etc climb it there it seemed to me that whilst he no doubt has immaculate technique for vert/slabby gnarl or malham trickery, the overtly 'less technical' flicking employed by those more at home on 50 degree ground was actually the better technique in that arena. If you watch videos of Andrada's spinny, campusy style - initially it often looks like 'poor' technique, but actually there's often a lot of tricky momentum going on behind the scenes.I have no advice to give on exercises to do at home, other than the usual shit for getting stronger fingers, arms and core. The real advice is: build a steep board, go bouldering on steep stuff more, or move nearer to a wall...
I expected too much of my already gained experiance on non-steep rock would transfer to something i'm not used to. Massive head room for improvement on it though I guess!
My 2 cents. Core doesn't involve just the lower back and legs, it involves the whole body. It means being able to be strong from the fingers on the hold, to the toes on the footholds, so a strong upper torso, and strong shoulders are a must have. Also, on overhangs the push from the feet in my opinion must be more progressive, otherwise with a sudden, quick push you'll get very high but you can cut loose. This is something I trained by avoiding the classic feet-follow-hands kind of gym setting, and by setting my own problems, using poor feet and choosing holds on which a cut loose meant a fall.
The good news is that steep stuff is less technical - usually there is a lot less possible moves than in vertical or slab so its quick to learn and once you get the fitness part and the basic movements wired you'll be crushing.
Watching the wads up at Rubicon et al has shown me that strength and good, accurate dynamic movement can work wonders.
I know you said you cannot afford the indoor walls at the moment, but this:http://www.onlineclimbingcoach.blogspot.co.uk/2013/05/old-school-drills-foot-off-bouldering.html