So hey all returning to this sport after a couple of decades, sailed every few years but essentially consider myself a noob. I bought myself a Tabou Rocket 126l with a couple of sails and a little bit of gear, in retrospect paid to much

but needs to start somewhere. Any way a couple of days ago i headed down to the local lake with a promise of 10-15 knots thinking an ideal day to start. On arrival looked much stronger checked the local weather stn which described 24knots with 30+knot gusts...so i rigged my 6m daytona free ride sail and went for a sail. Now my initial mistakes where
1. footsteps too tight
2. harness lines way too short , maybe chest harness lines?
I was going ok - didn't feel overpowered (i am 100kgs) but certainly out of control. harness and footsteps had me struggling ended up catapulting through my sail

not sure that this is worth repairing.
So my questions, i know they may seem ridiculous. How do i buy a quality second hand sail? what sort/type do i choose? do i buy a mast boom mast base to suit? does this lock me into a particular brand/type? i understand mast base can provide power or control fore or aft(can't remember which one)?
Am i crazy starting on this board?
How can i regain some control?
Thanks for your help i appreciate any advice