i'll try and explain in detail for you - but as it's complex (and difficult to write) i'll just do your james grieve - which produces fruit on short spurs
to encourage good growth - you can prune your laterals in winter - to 3 or 4 buds
once your tree is established you are ready to use a pruning technique which is referred to as the renewal system and is aimed at encouraging new growth each year - to replace what has already borne fruit
it's a long process in fact and you have to be patient - and i'll try to explain in more detail.
year 1 - a growth bud sends out a shoot
year 2 - the shoot produces fruit buds
year 3 - fruit buds form spurs and bear fruit - and will continue to bear fruit from these spurs
however in the 2nd year - the shoot not only produces fruit buds - it makes tip growth too - so it is a 2 year old shoot with 1 years new growth
equally - in year 3 - you will have 2 year old and 1 year old growth on your shoots - with the renewal system you cut back your 2 and 3 year old shoots - which stops overcrowding and should improve cropping and fruit quality
you have to decide the shape and balance of the tree - ie growth v fruit
try not to let your tree to become overcrowded with branches or overburdened with fruit - that's where the art of pruning comes into it's own
try and keep 1 year old growth that comes from your main branches as this will be part of the renewal system in a few years time
i hope that this makes sense to you - pruning is all about balance - you are telling the plant what to do when you cut a bit off - you are telling it to produce better growth or more fruit - or for perfect balance more/less fruit on strong growth