I’m a die hard 9c 1.0 guy. I love my 9c 2.0 as well. Having said that. Go for the 17 round mag first. It’ll give you a chance to test out the included mag adapter.

Magcommander
$23.49 in stock
17 round
Smith & Wesson M&P 9mm 17 Round Magazine – Mag Com

Great price on 15 round but out of stock
$23.99
Smith & Wesson M&P M2.0 Compact 9mm 15 Round Magazine – Mag Com