What Showing Class Would you Recommend?

Question:
Dear Claire,
This is my rising 6 year old Irish Sports Horse gelding, he is 16hh.
I would like to start showing him this year, what class would you recommend for him for his build?
We seem to have Riding Horse or Ridden Hunter classes around my location but not so much lightweight Hunter, so would like your advise on what class would suit his build best.
Also is a shirt and tie expectable or a coloured stock with my tweed jacket??
Many thanks,
Hayley. Shropshire

Answer from Claire:

Dear HayleyWe recommend you show your horse in ridden hunter classes, and if he is illegible for ID classes I would definitely show him in those.He needs to  put on a lot more condition, and you need to take 5 inches  off his tail as well as trim out his heels.A shirt and tie is acceptable with your tweed jacket.Good luck and do not hesitate to contact us if you need any more help.Kind regards,
Claire Oliver