Were not talking about movement here. One eighth of an inch will be plenty. Just enough to relieve the pressure.

A rubber pin to hold the adjuster? Just kidding. But you get the idea.

I see this getting more and more complex, has anyone just tried putting in a weaker spring? Maybe 60% strength of stock. Leave everything else like we run now. Go to a extension when necessary. I like the K.I.S.S. method of wrenching.

My guess is that the ratchet teeth are about 1mm so we get 1mm free so to speak.

The real question is how much does the expansion  take up of the slack in the chain. If it is indeed 1.5mm then we need to find more than that.

I think as long as the chain cannot move back too much we are ok. Thus placing a solid rod inside the spring will achieve this.
The pawl is the problem. When it has just taken up a new tooth the expansion of the cylinder is more than the mechanism can accommodate and the chain is placed under extreme tension. I don't think there is a problem with not having a pawl, as long as the rearward travel is limited somewhat.

The stock spring provides the tension most of the time it is just when a new tooth has been acquired that we have a problem due to the pawl.

I askkid my maw why she throwd out my paw,she sayed he was a be'in a pain in her chain.She throwd him out and aint looked back agin'.

I hear you batman. I  just haven't got the guts to remove the pawl without some kind of backlash protection.

Removing teeth from the plunger won't work.  The pawl has 2 teeth, so if you remove every other tooth from the plunger....the only thing you will accomplish is having only one toot of the pawl engaged with he remainng teeth on the plunger.......the plunger will still ratchet at the same rate.

When I wanted a weaker spring....I just went to the hardware store and matched one up in diameter that was considerably weaker and a similar length.  I measure the plunger extension with the stock spring, and with the new lighter spring the plunger was pushed out within a half mm of the length the stronger spring pushed.....close enough for a trial run as far as I was concerned.  The spring does nothing when the engine is running as the pawl is doing the work.....the spring only moves the plunger when the engine is at rest and cool, and likely the pawl takes a new set as the starter first turns the engine over when doing a "cold start".

The space between the teeth on the plunger was a bit hard for me to measure with my calipers. It appears that there was 0.910" of teeth on the plunger, and it has 23 teeth as best as I could count.  That results in about 0.03956" per tooth - or about 1mm each.

Here's a crazy idea for a manual cam chain adjuster: How about a ratchet device like the brake adjuster in an old drum brake system, adapted to fit where the chain tensioner lives now. The hydraulic oil sightglass could be fitted to the side cover, and removed to adjust the chain slack with a  flat blade screwdriver. Obviously a bit of user skill be need to get the right tension but it might work...

So the new stronger spring would actually fulfil the roll of keeping the chain tight and preventing the plunger from ratcheting out until the chain had stretched to the point where the new springs tension was less than the plunger spring tension at which point the plunger spring would take over and allow the plunger to advance a tooth. Is that how it will work?