Sorry I'm not an expert, but why not to take colemas at home and save time money and energies, not to talk of the advantage of being you the one that decides what, when and how long etcetera?
In the book of Bernard Jensen : Tissue Cleansing through Bowel Management, there is a very detailed description of how to build boards and do colemas (you can find this book also on-line somewhere, sorry I can't be more precise) and also what protocol to use. He tends to use far too many supplements for my taste and my wallet, but the very necessary things are bentonite, psyllium and probiotics after, as far as I understood.
Another source, less detailed: Daniel Reid, The Tao of Health, Sex and Longevity. He suggests to use Greenlife after the researches of dr. Irons (a pioneer in the bowel cleansing) that you can find on the net at www.awerenessinstitute.com, together with other very good products.
Also veru interesting the two books of Richard Anderson, who also sometimes writes on this forum and sells on the net everything you need.
By the way Anderson stresses very much the emotive component of the 'guts' problems and I don't see very well you taking vacation from work and travelling hours to Houston and spending flows of money and then taking your colonics 'the most relaxed you can'!!! come on, no wonder you doubt it works!
(Anyway there are tons of other good books on the subject, you can find some titles on www.sheilas.com)
You don't feel like getting colemas or enemas? Use herbs! Like Holistic Horizons after dr.Gray or many many others you find in the net. Make a Master Cleanser fasting adding B&P and salty water flush (that by the way is a very ancient indian practice called shankprakshalana)... you have a world of possibilities just waiting for you to take care of yourself just the way you like.
And whisper to your body words of love, it seems the usual banality but really it makes a great great difference! Breath deeply, calm down from your worries and smile to your dear suffering body, tell it everything is going to be OK, with time and dedication but without effort and sacrifice.