Hi Giles, I started using 2" for high magnification but found myself going back to 1.25" each time, in my opinion you don't need wide field for planets or Moon, if the 1.25" does the job well enough why bother with the extra expense (along with filters, of course, which are double).
I have never found using a 2" Barlow very satisfactory and sold mine, as you say, weight considerations is another factor and overkill on a 130mm reflector. Do not think of 2" as an upgrade, I found that this was a mistake, buy for what your target is, don't generalise too much if you can afford it.