What is the adverb form of "custom"?

What is the adverb form of the adjective "custom"?

custom

adjective

• made specially for individual customers.
• dealing in things so made, or doing work to order.

The adverb form of the noun "custom" is "customarily". However, this question isn't about the noun; it's about the adjective.

Solution 1:

The advebrb of custom in the sense specified is custom, as in:

They custom make airbrushes for specific applications.

We custom build each ad from the ground up

He custom built pull-out drawers and added dividers measuring slightly over 6 inches.

We custom make each brake line to your exact specifications

We had it custom fit without the train and it was beyond breathtaking.

You can also get it custom engraved for an additional $10.