Gear/tips for improving

I would consider myself beginner - intermediate and I want to know any tips or gear for getting better. I'm a light sailor (60kg) and I run a 170L starboard go with a 5.3m free ride sail. I can plane at 12-18 knots (board planes easy as), and I prefer planing without foot straps due to the board layout. I don't have a harness, so how necessary actually is a harness? My hands get absolutely demolished since my skin hates water and the boom essentially tries to de-glove me after get back after falling in. Would a harness help with this? I was also wondering about board and sail size. Would it be good for me to move to a larger sail and small board? Like up 6-6.5m range and a 120L board. Plus are smaller boards better if I try move to chop/swell? Any help would be greatly appreciated

The Go has a bunch of footstrap options, from the way inboard "beginner" position, one in the middle, and one out on the rails. Once you're using the harness, try out each of them! I started getting comfortable planing with a harness with the footstraps in the middle position as it seemed like a good compromise compared to where I'd put my feet normally, but I'm also using a much bigger sail due to my heavier weight (75kg/193cm). After getting comfortable, I could tell that the straps really needed to be on the outboard position when properly powered up, so that's where they are now.