Welcome and what a great start, the king of SIBs and it does not get better in SIB land than that.
Fairy Power Spray is a favourite for tube cleaning together with a gentle scrubbing brush.
When I did the transom on my Y I used Scothbrites and meths. I did not really want to use a chemical stripper but you can do that. Regardless go careful near the fabric joins. Otherwise work though the grades of abrasive paper. A decent two pack varnish will work well or you can go down the frequent application of specialist oils.
And pics are obligatory please.