Offa's Dyke in June

hello

I live the USA and am looking at doing the Offa Dyke in late May and June.

I would like to know if you would suggest it or point out it being a poor plan? Is the trail extremely busy during that time? Is planning on 19 walking days realistic plan for the full trail?

Also in a thinking of looking at booking the hike Macs Adventure or Celtic Trails, so that I can walk with a day pack and have the logistics worked out for me. Would you recommend either company?