Cayin A-100T KT88 tube spec

Not clear (to me at least) what you are asking. Does this amp have a bias adjustment, but you can't adjust it enough with a new, presumably different brand of kt88's?

If the new tube does not reach the factory-recommended bias level, it means that the new tube is probably weak, has low Gm.
New KT88s come in a wide range of Gm, from 6000 to 8500.

Try to buy a matched pair around 8000 GM and 80 mA.
This is just a guess, I have no insider information about your amps.

I have the A-100T - attempted to use KT88 and 6550 - Could NOT ADJUST BIAS.
Apparently the engineer at VAS has modified the unit (I was there) to allow ONLY the EL34 family of tubes. This means KT77 as well as 6ca7 types.
Be advised - the number - matching number that is - NEEDS to be from 28 to 34. Recently was provided an Octet of GL KT77 @ 22. I was able to set BIAS at the 9 hour use setting BUT from my experience with 'other' tubes - the final setting would or could not be achieved. I removed them - they are on their way back to the supplier.

A100T came in 2 versions ,100wpc ultralinear using 6550 kt88,, other version using EL34 ,75wpc ultralinear ,need to perform resistor change if you wish to switch from EL34 to 6550 etc,,.per Steve at VAS industries...
P.S. A100T sounds better with the EL34s my opinion anyway..

I have an A100t, EL34 version and know someone who could perform resistor change to use KT88's but he needs to know which ones and what the new type needs to be. Can anyone help? Thanks