Client wants a spa installed. There is a perfect spot for the disco with a 50A GFCI breaker in it, but the only clean way to connect up is the exterior 100A breaker at the meter. Tying to the panel inside the house will cost too much and kill the job.
If the disco and breaker are close enough, can double lugging the load side of the 100A breaker be considered per code under the tap rules?

If not, what are my alternatives?

Thanks for your help