This is a very individual opinion so here goes. Oil based is best on pine especially old rough pine. Stick with oil based right through. The system is knotting, primer, undercoat, undercoat , gloss. In order 1.knotting patent thick knotting or 2 coats of bin. Do not sand. Just around knots of course. 2. primer very important I prefer sandtex flexi primer/undercoat but as an undercoat it's a bit thin. To primer especially if you've had these dipped or any chemicals potential adhesion problems add a good dash of owatrol.
3. Undercoat on old work needs to be thick and to rapidly dry, build, then be easy to sand. If yours are indeed stripped and clean the stick with sandtex flexi undercoat if there old and chipped/cracked use coverstain as oits much thicker and dries in 2 hours. This is in essence filler paint.
4. Gloss I like sandtex they do a satin as well. Its pre mixed.ive been using dulux trade weathershield this week and whilst fine it's not as forgiving as sandtex. It's got lots of driers so skins in the tin an takes forever to mix completely being mixed in the shop. To thick and it wrinkles so it needs some owatrol and some white spirit. All oil based paints are needing black bristle brushes ideally or failing that Purdey monarch Pro extra. And a paintmate to keep them wet. Every few hours of painting rinse your brushes in white spirit otherwise they drag. Avoid plastic caulk and fillers esp on bottom edges.Use putty if you've got time(toupret can be painted in 6-8 days) gras a lacquer on small shallow fills. But undercoat your friend on old stuff.
