All good boaters should know a few splices!!
If you can tie an albright knot you have the skills to splice.
Its not hard, teach yourself the eye splice and backsplice at a minimum. You will be able to customize you slip lines perfectly. Just don't let the guys on the dock see you splicing lines or you will have a pile of them to do!
Really!!!
The trick is pick out some decent soft 3-strand nylon line. Don't use the stiff old stuff that has been outdoors for 5 or 6 years. (BTW, you can "soften your stiff lines by putting them in your washer machine and soaking them in fabric softener.)