You cannot dynamically pass in variable quantities for individual Features within a Product. Note that each Feature does have a Quantity attribute that is a multiplier of the Entitled Quantity. So if Feature A is defined with Qty 1 and Feature B wit Qty 2, an entitled Quantity of 5 for the Product would yield 5 x 1 = 5 for Feature A and 5 x 2 = 10 for Feature B. If the fixed ratio does not meet your needs then the recommendation would be to put Feature A in Product A and Feature B in Product B so that you can have any desired combination of Feature quantities.
You'll need create two products representing the two features. Then when you create the entitlement, select or tick both Products. When going through configuring the policies for the entitlement, you can specify different counts for each.
