honestly if your dripping on your header i would not think the rear main seal is bad/leaking. make sure the oil pan drain plug is not stripped or cross threaded because this is a common honda problem. clean it good and let it leak and crawl under there and look. i know when i change my oil i drip on the header and it burns. i can say on my girls car i have seen an oil filter leak which would cause that to drop on the header. The oil pan gasket is not that hard to do, just make sure you follow the torque specs putting the bolts on, if not you will squeeze the gasket and trust me it will leak right onto the header. (had this happen when a shop changed my gasket, go figure i fixed a shps mistake!!!) also the rear main seal will leave a puddle more on the passenger side of the car if you park it level overnight. they do make products to stop leaks but i do not recomend it either. just make sure you check the oil often and add oil accordingly. it may cost a little money for the oil but you don't wanna blow the engine. BTW $600 is a rip off. i paid around $380 for my rear main to be replaced and that included the seal from honda(which i also recomend) clutch replacement and flywheel resurfacing.

i would save the money and have your swap done right. all seals, pumps, and belts done before you drop it in.