Whats the best length and action for a shakey head rod? Trying to keep this purchase under 100$ looking for a spinning rod also. Thanks

IMO, either a Medium X-Fast or Medium Fast at 7' or longer would be your best bet.

Medium Power/ Fast Action

8-)

One quick question about the actual technique of fishing a shakey head. Can it be fished in a medium current river for smallies  and would it be effective?

I'd say either 6'6" or 7'. Anything longer just feels too long for this technique. As for your second question, I've never been in the situation.

Some guys are starting to throw some pretty heavy shakey heads well at least around here.  I like my 7'1" med fast action loomis.  Great tactic and also if you drop shot you can cross over using the same rod.

7ft Medium Fast would be your best bet.

I guess I'm the exception. I prefer a ML F or XF in anything over 6'6.

I guess I'm the exception. I prefer a ML F or XF in anything over 6'6.

x2

I use my Loomis dropshot rod for it so am probably biased to a lighter action set up.

I'd get a ML X-Fast action 7'

I'd really look for x-fast.  I think this will help you get further cats if you are fishing finesse baits.