We've only done this 3 years, all on buckets. '06: 180 taps, 0.35 gal/tap; '07: 200 taps, 0.31 gal/ tap; '09: 230 taps, 0.38 gal/tap. No more than 2 taps per tree regardless of size and most had one. We do tap young fast growers down to 8" and had several of those.
Ian
New sugarhouse fall '06. 3x8 drop flue by Phaneuf. Kubota L2800. 260 buckets for 2012. 504 taps for 2013. 320 buckets, 207 on 5/16" and 200 on 3/16" gravity tubing for 2014. 2017: 280 buckets, 920 on 3/16" tubing, selling sap from 560 of that. Son Gavin is in 3rd successful year of selling maple equipment as MacK Maple Supply.