When there is no more room for adjusting the rear wheel in the right direction, the only option left is to alter the chain or belt length, i.e. the number of chain links or teeth of the belt.
Suppose you want to switch your sprockets form Current (14-36) to Custom
Using the current chain, you would have to move your rear wheel 0.49 inch closer
to the front. Now lets assume the rear wheel is already at the maximum front
position. This means the only option is a longer chain. A longer chain means a
New chain for which the wear percentage is 0% (as it is new) so change
the wear percentage for Custom to 0% and start experimenting with a
longer chain: To find out how long you
will have to experiment by changing the number of links.
This still means moving the rear
wheel 0.28 inch to the front which is not possible.
This means moving the rear wheel 0.04 inch backwards which IS possible ! So a chain with 96 links would be long enough for this sprocket combination.
As mentioned above, normally the minimum increase or decrease of chain links is 2 as you do not want to remove 1 link and replace the ends with a special connecting master link. (So always keep the number of chain links even, this is including the master link.)
For a belt the same calculations can be done for determining the number of teeth needed in the new belt. For a belt the number of teeth can be odd as a belt has no 'conection link' like a chain does.