for weightless plastics.   i use 14 pound test and do not use pitchin or flippin.  i would think a 6 1/2 foot medium.  seems like the research i did is all about backbone power horsing fish out of heavy cover and suggest a medium  heavy 7 foot  with 25 pound test.  not really my cup of tea.

i would think a 6 1/2 foot medium. .

Lots of people use a medium for weightless plastics.  All that matters is that you like it.

Much of what you hear people referring to a soft plastics rod means t-rigs and many (or most) also do use them for pitchin and/or flipping.  I like a med heavy for my weightless stuff, but when I throw weightless plastic it's usually a Fat Ika or a 5", 6" or 7" Senko, and I often fish them in or around heavy cover.

I generally use a rod rated for 1/4-3/4 oz lures and 10-17 lb line. Loomis MBR783 or St. Croix EC66MF, the loomis is rated MH whereas the St. Croix calls theirs medium. Rods differ alot due to the materials used. Compare an MBR782 in GL2 and IMX and there is a huge difference. But they are both rated MH, so go figure.

The length and power rating you choose has a lot to do with personal preference. I fish all soft plastics on a 7' MF spinning rod. Medium power has plenty of backbone for landing big fish and makes bass under 5 lbs more fun to catch. I think the power rating has more to do with the weight of lures you plan to use rather than the fish you  hope to catch. Medium Power fits me very well.

i like a soft m-h.it's not qyite as soft as a medium but softer than most m-h rods.the johnny morris signature series 6-6 mh is like this.