I have over a hundred cores. I use a bit of D2 arbitrage; buy either the Mars seraphite or Mercury simulation seeds from Spider for legendary shards. I prefer the simulation seeds because Brother Vance gives more legendary shaders than Anna Bray, that's important. I think it averages out to 1 masterwork core per 15 packages. I'll spend over a thousand legendary shards at a time, turning in the planetary materials for the weapons and shaders, dismantling them, getting back shards and weapon parts as well as the occasional masterwork core and mod components. It is time consuming as you have to buy 5 materials for per 1 legendary shard a button press at a time. You can't simply choose to spend a hundred shards at a time or purchase a hundred simulation seeds at a time. So it takes patience. I have purchased Alkane dust from Spider recently when I was low on glimmer. For some reason Sloane has been very generous to me with cores as well as the rare shaders that grant glimmer upon dismantling. So if you need to infuse your fave weapons, there is a way you can do it if you're willing to put in the time. Low on shards? Spider is known to sell shards for glimmer. When I've maxed out my glimmer I'll trade it for legendary shards when Spider has that choice available.