You should be able to adjust your pledge to another by viewing the project page and choosing 'Manage my pledge'. If there is an additional item you want not available in a reward don't worry, there will be a way to add items once the campaign has ended as long as stock is available!
If you select the Vinyl and CD package both will be signed. The current CD only option is not signed. If you send us a message we may be able to get it signed but can't promise until we have confirmed the distribution process!
Don't see the answer to your question? Ask the project creator directly.