Are you going to be using a bipod? I have the long 10/25 RD mag, and I had to get a tall bipod:
BIPOD-205 - Bipod Tactical OP Rubber Feet 8.3-12.7" Height Leapers UTG Picatinny Rail Or Swivel Stud Mount
when the bipod is fully extended, the mag clears the floor by about an inch. If you want some extra 10 rd mags, I suggest 44mag.com:
44MAG.com - Smith & Wesson - S&W .22lr 10rd Short M&P15 -22 Magazine Smith and Wesson
Hope this answers your question.