I have converted 3 vehicles with the DIY approach, and I have 2 waiting on me (my Dad's...)
I put the conversion fittings on, vacuum it down to boil all the moisture out, add 2 oz of pag oil, then recharge with 134A.
I also am no expert, but I have not had any trouble out of any I have converted. The vacuum step is important because moisture will cause long term issues. But, as ^^^^^ he said, what is long term? He hasn't had any troubles w/o vacuum.
Good luck.
