Are these approaches meant to be mixed, hicetnunc?
My latest thinking is that once you do a problem set in a single day (like finishing 7-circles) you then need to repeat this (i.e. solve the entire set in a day) with the same problem set at intervals, whilst at the same time starting a new set. Hopefully then you can keep the old positions in your head whilst you try to shovel new positions in.
There's a good blog on this here, this bloke has really thought about this stuff:
http://empiricalrabbit.blogspot.co.uk/2010/11/introducing-expanding-repetitions.html
The three basic approaches :
The three methods make you work on your tactics and help long term retention. Provided the puzzle set is adequate (ie. reasonably easy), they should help in some way.