In reply to 3Jas:
I have a similar sized board - 140ish cm wide, 40 degree, 260 cm high (actual board length around 3 m) -symmetric but not systems (there are a couple of photos accessible from my profile). In my experience, even such a small board is well worth having - if you cover it with enough holds, narrowness is not a barrier to years of varied fun.
I might recommend steeper than 20 degrees though, otherwise, as you progress, you risk having to use horribly small and skin-unfriendly holds to make sufficiently hard problems. A less steep board with small holds is admittedly good training for fingery wall climbing, but fingerstrength is perhaps best built with a fingerboard instead.
To my mind, a woodie is best used to build power and core strength. As a limestone sport climber 30-40 degree is my personal sweet-spot range for working fingers, power and core (if I bouldered more, I reckon 40-50 degree would be better).
Also, for resin, I second the recommendation for Bleaustone training stone holds - regular with decent texture. The Malcolm Smith Trainingstone holds are also good. But, my preference is for wooden holds. They can feel a bit slick and prone to "dry firing" but are far less abrasive than resin - you can have mutiple, successive sessions without problems. +1 to Mr Kettle's recommendations of Hardwood Holds (aka LX Holds) and Crusher.