I borrowed an All Hours as people had suggested it would perform well...My BB+ last better and I couldnt fit much in the way of extra boosting, I dont kow if thats typical or not though as Id only borrowed this one for the one night trial.
Have you tried an LLS superwetter?
I have recently bought large WNNN and with the extra absorbency and extra stuffing room I have found they are fabulous (having mostly fallen out with the mediums!) I put an extra 6 layer bamboo in the pocket with a zorb booster (plus the 4layer insert) then another zorb booster under the snap in part and it works very nicely indeed! It still sat nicely round his legs and hadnt moved a cm by morning and although it was wet on the outside it wasnt dripping (literally) like his night nappies often are. Much impressed.
The BB+ wide in M/L I have dont have too much room for extra boosting but I do put in an extra contour soaker and two extra zorb and they last very well but I have to jiggle it all a lot to get it to sit right in the nappy, hence I am switching to Toddler sizes and probably to serged to get some extra room for the boosting if his night wetting doesnt settle down again soon.
Oh, if you havent already got one a WCDNN with a bazillion piggybacks may work...I use six bamboo piggybacks plus a zorb booster and that goes overnight, bulky but works so I dont care!
You can always boost outside the nappy as well, I dont because T moves a lot in his sleep and I worry about it moving but in theory I could use a snug soaker with the boosting outside of the nappy, I just havent tried it yet as Ive gotten pretty comfy with the limited few that I know do good as I really dont want to end up fixing leaks etc when weve never had any!
How well lanolised is your wool? Could the PJs be too tight and making it wick? Tried longies with just a PJ top?