In case you aren’t aware, you can get a legacy license for Rhino 7 so you can have both 7 and 8 installed and usable. This makes it possible to install Rhino 8 and still have Rhino 7 available for fallback if there are things about Rhino 8 that are making your work difficult.
Keep in mind that even thought your Rhino 7 procedures and habits will mostly work on 8 there will still be some effort and discovery to get familiar with the new things that 8 can do. If you are using the default Rhino 7 toolbars, etc Rhino 8 will be very familiar. If not then there will be some effort (and some would say frustration) in setting up 8 to work like your customized 7.
So, personally, I think that your best course of action would be to install your Rhino 8 and start to use it to see how far you can get before you are dissatisfied. With the ability to write Rhino 7 .3dm files from 8 and having 7 still installed there should be practically no downside to trying it out. Hopefully if there are things that you don’t like you will report them in detail here.