Customize font in pick lists

In the interim, you can create your own picklists; since you can export order line items in whatever format you wish, you can create a format that has the info you need to generate the picklist, and then format this in whichever way you would like.

We find too that our generated picklists are vastly more flexible since you can change a great deal more (granular order, collating certain skus even when the marketplace forces import of an alias, categorizing certain skus, etc) than is possible in the default shipstation picklist. 

EDIT: 

While you don't have access to the batch column in normal exports, if you export "current view" and have the batch column in your current view, you can gain access to it this way. Then you can use it create all picklists for all batches at once, which is what we have been doing.