I usually run 2 to 1 veg derv mix with a shot of forte every other tank full.
Starts and runs fine with no loss of mpg's but does hunt for 5-10 seconds on a cold start. Not an issue for me as I always try and let it idle for 30 seconds or so to let the engine oil circulate (rolling a smoke is my usual guide on that).
If it's running lumpy I'd give it a good dose of your chosen cleaner, if possible a full dose with low fuel will give the pump and injectors a good scrub, then try a higher veg mix.
When it gets colder I'll move to a 50/50 mix which will increase my price per litre but at the moment I'm paying £1.14 a litre instead of £1.41 for straight derv and rising!! Saving me £1.22 a gallon or put another way it pays my road tax
At the moment I'm getting forte FOC from the guys in the workshops so I'm planning to experiment with some veg in a bottle mixed with it to see if it actually thins it or not, will post the results when I get round to it.