I have used both S&S Quickies & SE Premium Tapered pushrods. Some people prefer the SE Adjustables, which can be bought cheaper from online HD vendors..

https://www.shoputahharley.com/produ...SABEgIBW_D_BwE

I have actually invested quite a bit into torque wrenches, but use them frequently and for many years...You can get a digital torque plus angle wrench for $600... But no need to get carried away with a super quality torque wrench, if only for sporadic use... I built a '64 Olds 442, back in 1977, with an old Sears beam-type torque wrench.... that car held together and was still going strong when I sold it... While I don't use it anymore, I still have that torque wrench..

I would hesitate to buy a used torque wrench on eBay, unless I could be confident it was cared for...... Just little things like throwing it in the drawer, without first releasing the tension on it, can mess up it's accuracy over time..

Probably any big-box store torque wrench will work for you.. just remember to make sure to get one that will cover the torque range(s) for which you plan to use it ...

Welcome to the world of wrenching on your bike.. I actually enjoy it, but at the least you'll see it's not rocket science. It's fairly easy with the HD manual, and online resources will let you in on tips/tricks to make it easier... Enjoy!