No. 15# braid has the strength rating of 15# mono. It has the diameter of 4# mono. So you get better strength and castability in a smaller line compared to mono. 20# braid is about 6#, and 30# braid is about 8# mono, and 40# braid is about 10# mono. In diameter. and 50# braid has the diameter of about 12# mono.
May I suggest something?
It sounds like you are still trying to get your feet wet on some basic things, and you are planning to use spinning-only "for now". I was a spinning-only person for many years, even for punching, pitching, frogging, etc., until recently. But I also never bought expensive rods like an Avid. I have and still use a MH spinning spinning rod for some things -- it's an adequate rod (a blackout), but it's emphatically not a $200 rod. I am very glad I never spent $200 on a MH spinning rod because most of the things I used to use MH spinning for, including jigs, buzzbaits, spinnerbaits, and other heavier lures, I now use casting for. Had I bought a higher-end MH spinning rod, say, 4 years ago when I was using that sort of thing more often, by now i would certainly wish I had gotten an MHF casting rod for these presentations instead.
I have no problem recommending an Avid X spinning rod --my preference is the 68MXF, but as you can see here good cases have been made for the MLXF and for the MF. But for the other, heavier things you want to throw, be very sure that 2, 3, 4 years down the road you aren't going to wish you had gotten a casting rod instead. Good, expensive rods should be things you'll be happy using a lot, for a long time.
If you are dead set on getting two AVID X rods, get one spinning (ML or M) and one MH-F casting instead of two spinning, unless you have very good reason to believe you will not wish you had gotten a casting rod instead a couple years down the road. Alternatively, buy a lower end MH spinning rod ($50-$100 range) for your heavier baits to use for now, with the understanding that your tastes may change with experience, and possibly sooner than you think.