Chain vibration in smaller cogs while on KICKR (ie any tips on indexing reliably?)

I had my gears indexed perfectly on my road bike (Di2), but had some issues on my KICKR. Which is fairly normal, I’m told. (any non-Di2 riders, I’d still love your input. My main issue isn’t necessarily Di2-specific)

I totally understand the process of HOW to index - I just can’t tell when it’s right!

No problem, I thought. Di2 adjustment is easy to do. You don’t even need to get off the bike.

Problem is, I find it really hard to hear exactly when the chain is lined up properly. I mean, I tap the chain several notches either way, and it takes a lot of adjusting before I feel the chain vibrating.

I’ve tried getting off the bike/trainer and turned the pedals to see where the RD is lined up. But it’s kind of hard to see on my bike.

At the moment, gears are indexed so that it’s not clicking, but it’s way louder than on my road bike. That’s almost silent. I’ve tried adjusting left and then right while pedalling, but I can’t find any sweet spot where the chain really quietens down.

Also, right now, there’s significant chain vibration in my smallest cogs. Does anyone have experience of what that’s caused by? Does that mean the rear derailleur needs to go further right or left?

Sorry, still learning the ropes with this kind of thing!

What cassette is on the Kickr? Cheap cassettes can often be louder.

The other candidate is vibration through the body of the trainer. This is quite common. Caveat: I don’t have a Kickr, so that previous comment is generic.

Cassette on the Kickr is Shimano 105. Definitely installed properly.

Vibration is the chain for sure. I can see it and hear it.

You’re going to feel different things on the trainer than on the road. My bike on my H3 is also a little “rough” in the outer gears, I just don’t tend to use them outside of bombing down alpe du zwift so it’s not a big deal.

I have the same issue, and what’s worse it’s like it rubs on right side in smaller cogs, and on left side in bigger cogs, and I’m not really sure how to index that. I feel like I should adjust whole derailleur somehow instead of just adjusting barrel adjuster but I really don’t want to do that coz it would then make problems when I take off my bike again.