May be a few scanned prints of what you have done may be more of a help, i use both a con, and a diff, the LPL 7700 as you. My times for print down time is set by what the test strip time are at a given F stop. Try using different stops for the test, until that is you are used to the type of enlarger. It did take me a while to understand there are small differences between the two types, not much but they are there. I do find if i get to little of contrast and do not want more blacks, i will add a little blue dial (.5) to the print and reduce the red.

Graham