Way late to the party here, but to return to the first post, I would suggest concentrating more on using a shavette since it seems to be working for you. As a long-time straight razor user, I had a bit of trouble with shavettes because they would mysteriously nick me at times when a straight razor wouldn't. The shave itself also felt more aggressive and rawer, not as smooth. These were with all-metal models. Then, a few years ago, I tried a Focus R21 which has a plastic sleeve to hold the blade, rather than metal. Here, I found the shave smoother, and I was able to make my normal two passes with touch-ups without nicking myself, yielding close shaves. Thinking it might be about the plastic sleeve, I picked up an actual Dovo Shavette which also has one. It too provided smooth, close shaves.
That leaves the problem with your jawline and having a completely successful shave with just a shavette. For a long time, I had a problem with the area beneath my jawline. I would stretch and pull my skin taut and could get close with touch-up passes, but it was always an effort for me. Then, and based on my limited experience with a safety razor, I tried something new: after the second pass, an upwards pass from the base of my neck up to and just over my jawline. This worked much better for me, better than stretching to make an ATG pass from where my jaw meets the ear moving towards the chin.
May also have to do with what blades you are using in your shavette. If you haven't tried already, I would suggest trying a range of mild, medium, to aggressive blades to see if one of them improves things in the problem area.
That leaves the problem with your jawline and having a completely successful shave with just a shavette. For a long time, I had a problem with the area beneath my jawline. I would stretch and pull my skin taut and could get close with touch-up passes, but it was always an effort for me. Then, and based on my limited experience with a safety razor, I tried something new: after the second pass, an upwards pass from the base of my neck up to and just over my jawline. This worked much better for me, better than stretching to make an ATG pass from where my jaw meets the ear moving towards the chin.
May also have to do with what blades you are using in your shavette. If you haven't tried already, I would suggest trying a range of mild, medium, to aggressive blades to see if one of them improves things in the problem area.