So I’m trying a lager for the first time (Schwarzbier) should I pitch 2 packages of yeast or use a starter?
Thanks for the advise, I really appreciate it.
Yes. 
For 5-6 gal of average-gravity lager, one pack in a 2-3 L starter, two packs in a 1-2 L starter, or four packs direct pitched.
This is what I do. No problems whatsoever.
Dry yeast or liquid?
Or pitch an active starter to wort with plenty of O2 in it. Easy peasy
By the way, forgive any nit pickery tone here… lager is a yeast strain, lagerING is cold storage conditioning. [emoji41]
2 packs of dry yeast (rehydrated as directed) is what I would recommend for a first lager.
My last 3 lagers I have pitched one can of Imperial Organic Yeast with no starter. Had visible and vigorous airlock activity within 12 hours. I have been very happy with the results. Cans were fresh (less than two weeks from “canned on” date.)
I did a dozen lagers with no starter or O2 until I had a problem. Now it’s starters and oxygen no matter what. Dumping beer sucks.
In this case I think you are fine not making a starter. In any case where the yeast has some age on it a starter would be very beneficial for a lager or use a good dry strain. 34/70 makes a fine lager.
I will add, if you are pitching a lager yeast at fermentation temps (say 48-52) and getting activity 12-24 hours later, you know you pitched enough yeast. If you are having to pitch warm to get the yeast started then cool down to fermentation temps you aren’t necessarily pitching enough yeast.