Good luck with the SPTA, I don't know if things have changed with them, if not, only a Traditional Korean Bow (as in true hornbow) will suffice. I looked at this society a few years ago, when getting short shrift from the usual suspects (GNAS, IFAA, NFAS) they were keen on traditional materials for bows, strings, arrows et al.
Not too many places suitable for a 145m target, other than Clout or similar, roving marks for instance. You should find a welcome with Clout archers but you will still have no category and therefore confined to informal meets.
I've just looked at their website, it looks revamped and it seems a lot busier than it was. Hilary Greenland is a member of this forum and I know that she has attended the WTAF (competed with Carole Edwards of Carolearchery in the team event.)
I used to get my wooden shafts from Carole and she brought a Hwarang back with her. She loved the bow, found transition to thumb release very awkward and chuckled as she told me that it didn't want to shoot close targets
Please be sure to let us know the outcome of this one.
Thanks for the continuing support, Hun. I, recently, met Carol and she has agreed to assist me, already. I am looking forward to next week when we begin, in earnest.