Clumping can decrease yields. I wonder how/why you get clumping? That should not be happening. I would not proceed if clumps are present. I would fully dry the paste (e.g. in shallow baking dish in oven at lowest heat) and grind again to remove the clumps. Them add water to (hopefully) re-form a smooth fluffy paste. For some reason, a little water helps mescaline move from the plant into EA. Maybe you can try this with your spent paste (dry the solvent in a well ventilated area though). It's always a good idea to keep everything until a new process is working. You can also try an EA pull right after grinding before adding water, see what happens when you add citric to that pull.
What kind of lime do you have? It is Ca(OH)2, and not something like CaO, right?
Do you stir the paste very well before microwaving? As you stir initially, the paste will 'resist' stirring, then over the next few minutes of vigorous stirring the texture will change towards a fluffy consistency that is easy to stir. Next, as you begin to microwave and stir this, it should liquify, them as more water is lost while stirring it should become fluffy again.
You can skip the microwave step if it gives you clumping issues, that process can still give xtals. EA will get a lot greener, and the xtals will be smaller and have off colors, but I still get xtals consistently this way.
We did dry EA chemichally but didn't notice any improvements to yield (got xtals either way). Experimentally CaCl2 pellets where best (mush easier to decant, less of a mess, not acidic). You can try this, see if helps.