If you want to come out on top of the 4%, make your price +4%, but don't explicitly say use gift option.
There is no ethical rule or explicit SF rule on what you price as long as you do not imply that you can choose gift/personal payment or regular+4%.
Meaning if you want to sell an item for $200, but don't want to lose on the $8 fee, make your full price 208.34 - regular payment NOT gift/personal payment. Then the price evens out to the 200 you intended to receive after fees. Don't mention it as a surcharge, just make it into the cost of the price of the item.
No need to mention that the price is set up that way for that reason, because there is no rule saying you can't list at 208.34.
tl;dr: If you want to list prices so that fees do not affect you, but rather the buyer - and the buyer pays with regular payment (non gift/personal) - take your intended take home price and divide it by .96. Round up or down if you want it to be an even number, or to the nearest 10 etc.. its up to you.
If I am just completely wrong, just let me know, my ignorance may be high here, but it just doesn't seem like a big deal to me to charge more for an item because there is a fee involved as long as you are not explicitly saying that because of the fee im gonna charge you 4% more.