You did very well!

One trick you can do is to leave the reduced tea sit overnight. The finest insolubles will settle and it will be easier the decant/filter the supernatant liquid. The bottom gunky part is hardest to filter but something like cheesecloth will do (I use cheeseclots and then cotton plugs + vacuum).

Another trick is to re-acidify (salt) your alkaloids in a small amount of water, filter, re-base, filter, and THEN do Manske. You will be surprised how much gunk gets removed by just switching to acid one more time. The Manske step will then work with less impurities thus giving bigger crystals and higher yield.

Washing the freebase alks with clean water few times also helps to improve purity.

Finally, if you have access to vacuum filtration setup with Buchner funnel, you can pass the acidified extract through a bed of Celite (or food grade diatomaceous earth). This will remove the finest impurities. I sometimes get tea that is so clear it even does not start to crystallize until scraping the beaker. It looks like red wine

Of course doing the Manske more times will push the purity further since this is basically recrystallization by dialysis.