Lag screw length for project using Unistrut

Needing advice on mounting unistrut overhead in order to hang a pneumatic hose reel. I have 2x4 framed plywood shelving in my garage and am planning on attaching two parallel lengths of slotted strut material to the undersurface of the 2x4 joists then attaching the hose reel bracket to the strut using 3/8” bolts into spring nuts. I have four 3/8” x 2” hex lag screws to attach the strut to the joists. Am I gonna be safe with that size screw? I think I am, but then again, I don’t do this for a living, just watch too much YouTube. Cox hose reel and 50 ft air hose. Not sure of exact total weight. Thanks for any input.